JEEChemistry

Electrochemistry

117 JEE Chemistry previous year questions on Electrochemistry — options free on every question; 12 include the answer & explanation free, the rest unlock with PYQ Pass.

Q1 FREE PREVIEW
PYQ
From the following select the one which is not an example of corrosion? [Re-NEET 2024]
aRusting of iron object
bProduction of hydrogen by electrolysis of water
cTarnishing of silver
dDevelopment of green coating on copper and bronze ornaments
✓ Correct answer: b) Production of hydrogen by electrolysis of water
ExplanationThe option that is not an example of corrosion is: B. Production of hydrogen by electrolysis of water Explanation: A. Rusting of iron object is a type of corrosion where iron reacts with oxygen and moisture to form iron oxides (rust).C. Tarnishing of silver involves the formation of silver sulfide on the surface of silver items due to a reaction with sulfur compounds in the air.D. Development of green coating on copper and bronze ornaments is caused by the formation of copper carbonate or copper chloride, known as patina, which is also a form of corrosion.Option B refers to a chemical reaction in which water is split into hydrogen and oxygen gases through electrolysis, and is not related to the process of corrosion.
Q2 FREE PREVIEW
PYQ
The role of fluorspar, which is added in small quantities in the electrolysis reduction of alumina dissolved in fused cryolite, is
aas a catalyst
bto make fused mixture conducting
cto lower the melting temperature of the mixture
dto decrease the rate of oxidation of carbon at anode
✓ Correct answer: b) to make fused mixture conducting
ExplanationThe electrolysis of is carried out in the steel tank linked inside with graphite.The graphite lining serves as cathode.The anode is also made of graphite rods hanging in the molten mass the electrolyte consist of alumina dissolved in fused cryolite and .Cryolite lower the melting point of alumina to and . increase the fluidity of the mass, so that the liberated aluminum metal may sink at the bottom & it is tapped off.
Q3 FREE PREVIEW
PYQ

\({\mathrm{E}}_{{\mathrm{Cr}}_{2}{\mathrm{O}}_{7}^{2-}/{\mathrm{Cr}}^{3+}}^{\mathrm{o}}=1.33\mathrm{V}{\mathrm{E}}_{{\mathrm{Cl}}_{2}/{\mathrm{Cl}}^{-}}^{\mathrm{o}}=1.36\mathrm{V}\\ {\mathrm{E}}_{{\mathrm{MnO}}_{4}^{-}/{\mathrm{Mn}}^{2+}}^{\mathrm{o}}=1.51\mathrm{V}{\mathrm{E}}_{{\mathrm{Cr}}^{3+}/\mathrm{Cr}}^{\mathrm{o}}=-0.74\mathrm{V}\)

Mark the strongest reducing agent.
(Memory Based JEE Mains 24/01/2025 ,Shift -2)

a

\({\mathrm{Cl}}^{-}\)

b

Cr

c

\({\mathrm{Cr}}^{3+}\)

d

\({\mathrm{Mn}}^{2+}\)

✓ Correct answer: b)

Cr

Explanation

Greater the reduction potential , lesser will be the tendency to act as reducing agent

Q4 FREE PREVIEW
PYQ

\({O}_{2}\) gas will be evolved as a product of electrolysis of

(A) an aqueous solution of \(AgN{O}_{3}\) using silver electrodes.
(B) an aqueous solution of \(AgN{O}_{3}\) using platinum electrodes.
(C) a dilute solution of \({H}_{2}S{O}_{4}\) using platinum electrodes.
(D) a high concentration solution of \({H}_{2}S{O}_{4}\) using platinum electrodes.

Choose the correct answer from the options given below

[JEE Main 2025, 29 Jan (Shift 2)]

a

(B) and (D) only

b

(A) and (C) only

c

(A) and (D) only

d

(B) and (C) only

✓ Correct answer: d)

(B) and (C) only

Explanation

Oxygen gas is evolved during the electrolysis of aqueous \(AgN{O}_{3}\) with platinum electrodes and dilute \({H}_{2}S{O}_{4}\)with platinum electrodes.

Q5 FREE PREVIEW
PYQ

Electrolysis of which compound give \({\mathrm{H}}_{2}{\mathrm{S}}_{2}{\mathrm{O}}_{8}\\\)
(Memory Based JEE Mains 22/01/2025,Shift -1)

a

Electrolysis of conc.\({\text{Na}}_{2}{\mathrm{SO}}_{4}\)

b

Electrolysis of dil. \({\text{Na}}_{2}{\mathrm{SO}}_{4}\)

c

Electrolysis of conc.\({\text{H}}_{2}{\mathrm{SO}}_{4}\)

d

Electrolysis of dil.\({\text{H}}_{2}{\mathrm{SO}}_{4}\)

✓ Correct answer: c)

Electrolysis of conc.\({\text{H}}_{2}{\mathrm{SO}}_{4}\)

Explanation

\(\mathrm{The}\mathrm{electrolysis}\mathrm{of}\mathrm{conc}{\mathrm{H}}_{2}{\mathrm{SO}}_{4}\mathrm{give}\mathrm{oleum}({\mathrm{H}}_{2}{\mathrm{S}}_{2}{\mathrm{O}}_{8})\).

Q6 FREE PREVIEW
PYQ

Identify the factor from the following that does not affect electolytic conductance of a solution.

a

The nature of the electrolyte added

b

The nature of the electrode used

c

The nature of solvent used

d

Concentration of the electrolyte

✓ Correct answer: b)

The nature of the electrode used

ExplanationFactors that affect conductance:
  1. Nature of electrolyte → determines type and number of ions ✅

  2. Nature of solvent → affects ionization and mobility ✅

  3. Concentration of electrolyte → changes number of free ions ✅

Factor that does NOT affect conductance:
  • Nature of electrode used → electrodes only allow current to pass; they don’t affect ionic conductance of the solution itself ❌

Correct Answer: (B) The nature of the electrode used

Q7 FREE PREVIEW
PYQ

A solution of aluminium chloride is electrolysed for 30 minutes using a current of 2 A . The amount of the aluminium deposited at the cathode is ________.
[Given : molar mass of aluminium and chlorine are \(27gmo{l}^{-1}\) and \(35.5gmo{l}^{-1}\) respectively]

[JEE Main 2025, 22 Jan (Shift 1)]

a

660 g

b

0.441 g

c

0.336 g

d

1.007 g

✓ Correct answer: c)

0.336 g

Explanation

Using Faraday's laws of electrolysis,

\(W=Z\times I\times t\)

Given:

\(I=2A,t=30min=30\times 60sec\)

\(∴W=\frac{M}{nF}\times I\times t\left(∵Z=\frac{M}{nF}\right)\\ W=\frac{27}{3\times 96500}\times 2\times 30\times 60\)


\(W=0.336g\)

Q8 FREE PREVIEW
PYQ

Fuel cell, using hydrogen and oxygen as fuels,
A. has been used in spaceship
B. has as efficiency of \(40\%\) to produce electricity
C. uses aluminum as catalysts
D. is eco-friendly
E. is actually a type of Galvanic cell only

Choose the correct answer from the options given below

[JEE Main 2024, 4 Apr (Shift 2)]

a

A, B, C only

b

A, D, E only

c

A, B, D only

d

A, B, D, E only

✓ Correct answer: d)

A, B, D, E only

Explanation

A. has been used in spaceship
Yes, hydrogen–oxygen fuel cells were used in Apollo missions.

B. has an efficiency of 40% to produce electricity
Fuel cells typically have efficiencies around 40–60%; 40% is acceptable.

C. uses aluminium as catalysts
Catalyst used is platinum (Pt), not aluminium.

D. is eco-friendly
Product is water, so it is environmentally friendly.

E. is actually a type of Galvanic cell only
Fuel cell is a galvanic (voltaic) cell producing electrical energy from a spontaneous redox reaction.

✅ Correct set: A, B, D, E

Correct option: 🔹 D

Q9 FREE PREVIEW
PYQ

On charging the lead storage battery, the oxidation state of lead changes from \({x}_{1}\) to \({y}_{1}\) at the anode and from \({x}_{2}\) to \({y}_{2}\) at the cathode. The values of \({\mathrm{x}}_{1},{\mathrm{y}}_{1},{\mathrm{x}}_{2},{\mathrm{y}}_{2}\) are respectively

a

+4,+2,0,+2

b

+2,0,+2,+4

c

0,+2,+4,+2

d

+2,0,0,+4

✓ Correct answer: b)

+2,0,+2,+4

Explanation

On charging , lead storage battery

PbSO4 → Pb at anode

PbSO4 → PbO2 at cathode

Q10 FREE PREVIEW
PYQ

Given below are two statements :
Statement I : Mohr's salt is composed of only three types of ions-ferrous, ammonium and sulphate.
Statement II : If the molar conductance at infinite dilution of ferrous, ammonium and sulphate ions are \({\mathrm{x}}_{1},{\mathrm{x}}_{2}\) and \({\mathrm{x}}_{3}\mathrm{S}{\mathrm{cm}}^{2}{\mathrm{mol}}^{-1}\), respectively then the molar conductance for Mohr's salt solution at infinite dilution would be given by \({\mathrm{x}}_{1}+{\mathrm{x}}_{2}+2{\mathrm{x}}_{3}\)
In the light of the given statements, choose the correct answer from the options given below

[JEE Main 2025, 7 Apr (Shift 1)]

a

Both statements I and Statement II is false

b

Statement I is false but Statement II is true

c

Statement I is true but Statement II are false

d

Both statements I and Statement II are true

✓ Correct answer: c)

Statement I is true but Statement II are false

Explanation

Mohr's salt : FeSO4(NH4)2SO4.6H2O
Using Kohlrousch law
\({\lambda }_{\mathrm{m}}^{\infty }\)(Mohr's salt) = x1 + 2x2 + 2x3

Q11 FREE PREVIEW
PYQ

Conductivity values (S m⁻¹) at 298 K:
2.1×10³, 1.0×10⁻¹⁶, 1.2×10⁻³, 3.91, 1.5×10⁻², 1×10⁻⁷, 1.0×10³

Find number of conductors

[JEE Main 2024, 31 Jan (Shift 2)]

a

4

b

3

c

2

d

1

✓ Correct answer: a)

4

Explanation

Classification based on conductivity:

Conductors: conductivity ≈ 10³ S m⁻¹ or higher
Semiconductors: intermediate (10⁻⁶ to 10² approx)
Insulators: very low (≈10⁻¹⁰ or less)

2.1×10³ → conductor
1.0×10⁻¹⁶ → insulator
1.2×10⁻³ → semiconductor
3.91 → this is relatively high → conductor (ionic conductor)
1.5×10⁻² → semiconductor
1×10⁻⁷ → semiconductor/insulator borderline
1.0×10³ → conductor

Electrolytes (like aqueous ionic solutions) with conductivity in range of ~1–10 S m⁻¹ are also considered conductors, not semiconductors.

Thus:

Conductors:
2.1×10³
3.91
1.0×10³
1.5×10⁻² (weak electrolyte → still conductor)

Total = 4

Q12 FREE PREVIEW
PYQ

Consider the following

\({\mathrm{E}}^{0}\mathrm{Value}\mathrm{for}\mathrm{the}\mathrm{given}\mathrm{half}\mathrm{cell}\\ {{\mathrm{E}}^{0}}_{{\mathrm{Ag}}^{+}/\mathrm{Ag}}=0.8\mathrm{V},{{\mathrm{E}}^{0}}_{{\mathrm{Zn}}^{2+}/\mathrm{Zn}}=-0.76\mathrm{V}\\ {{\mathrm{E}}^{0}}_{{\mathrm{Cu}}^{2+}/\mathrm{Cu}}=0.34\mathrm{V}{{\mathrm{E}}^{0}}_{{\mathrm{Mg}}^{2+}/\mathrm{Mg}}=-2.35\mathrm{V}\\ \mathrm{Then}\mathrm{which}\mathrm{of}\mathrm{the}\mathrm{following}\mathrm{will}\mathrm{have}\mathrm{the}\mathrm{most}\mathrm{negative}\mathrm{value}\mathrm{of}∆{\mathrm{G}}^{0}?\)

(Memory Based JEE Mains 23/01/2025 ,Shift -2)

a

\(Zn|Z{n}^{2+}∥C{u}^{2+}|Cu\)

b

\(Mg|M{g}^{2+}∥A{g}^{+}|Ag\)

c

\(Mg|M{g}^{2+}∥Z{n}^{2+}|Zn\)

d

\(Cu|C{u}^{2+}∥A{g}^{+}|Ag\)

✓ Correct answer: b)

\(Mg|M{g}^{2+}∥A{g}^{+}|Ag\)

Explanation

The cell which has most positive value of will have most negative value of.

\({{\mathrm{E}}_{\mathrm{cell}}^{\mathrm{o}}={\mathrm{E}}^{0}}_{{\mathrm{Ag}}^{+}/\mathrm{Ag}}-{{\mathrm{E}}^{0}}_{{\mathrm{Mg}}^{2+}/\mathrm{Mg}}\\ =0.8\mathrm{V}-(-2.35\mathrm{V})=3.15\mathrm{V}\\ ∆{\mathrm{G}}^{0}=-{\mathrm{nFE}}_{\mathrm{cell}}^{\mathrm{o}}\)

Q13
PYQ

What pressure (bar) of \({H}_{2}\) would be required to make emf of hydrogen electrode zero in pure water at \(25^\circ C\) ?

[JEE Main 2024, 4 Apr (Shift 1)]

a

\({10}^{-7}\)

b

\({10}^{-14}\)

c

0.5

d

1

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Q14
PYQ

For the electro chemical cell
\(M\left|{M}^{2+}\right||X|{X}^{2-}\)

\(\text{ If }{E}_{\left({M}^{2+}/M\right)}^{0}=0.46V\text{ and }{E}_{\left(x/{x}^{2-}\right)}^{0}=0.34V\text{. }\)

Which of the following is correct?

[JEE Main 2024, 5 Apr (Shift 2)]

a

\({E}_{\text{cell }}=0.80 V\)

b

\(M+X\to {M}^{2+}+{X}^{2-}\) is a spontaneous reaction

c

\({E}_{\text{cell }}= -0.80 V\)

d

\({M}^{2+}+{X}^{2-}\to M+X\) is a spontaneous reaction

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Q15
PYQ

Given below are two statements

Statement(I): Corrosion is an electrochemical phenomenon in which pure metal acts as an anode, impure metal as a cathode.

Statement(II): The rate of corrosion is more in alkaline medium than in acidic medium

In the light of above statements, choose the correct answer from options given below

[JEE Main 2025, 22 Jan (Shift 2)]

a

Statement-I is false but statement-II is true

b

Statement-I is true but statement-II is false

c

Both statement-I and statement-II are true

d

Both statement-I and statement-II are false

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Q16
PYQ

\({O}_{2}\) gas will be evolved as a product of electrolysis of :
(A) an aqueous solution of \(AgN{O}_{3}\) using silver electrodes.
(B) an aqueous solution of \(AgN{O}_{3}\) using platinum electrodes.
(C) a dilute solution of \({H}_{2}S{O}_{4}\) using platinum electrodes.
(D) a high concentration solution of \({H}_{2}S{O}_{4}\) using platinum electrodes.

Choose the correct answer from the options given below :

a

(B) and (D) only

b

(A) and (C) only

c

(A) and (D) only

d

(B) and (C) only

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Q17
PYQ

Correct order of limiting molar conductivity for cations in water at \(298K\) is

[JEE Main 2025, 3 Apr (Shift 1)]

a

\({\mathrm{H}}^{+}>{\mathrm{Na}}^{+}>{\mathrm{K}}^{+}>{\mathrm{Ca}}^{2+}>{\mathrm{Mg}}^{2+}\)

b

\({\mathrm{H}}^{+}>{\mathrm{Ca}}^{2+}>{\mathrm{Mg}}^{2+}>{\mathrm{K}}^{+}>{\mathrm{Na}}^{+}\)

c

\({\mathrm{Mg}}^{2+}>{\mathrm{H}}^{+}>{\mathrm{Ca}}^{2+}>{\mathrm{K}}^{+}>{\mathrm{Na}}^{+}\)

d

\({\mathrm{H}}^{+}>{\mathrm{Na}}^{+}>{\mathrm{Ca}}^{2+}>{\mathrm{Mg}}^{2+}>{\mathrm{K}}^{+}\)

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Q18
PYQ

For a strong electrolyte, a plot of molar conductivity against \({\text{(concentration)}}^{1/2}\) is a straight line, with a negative slope, the correct unit for the slope isEndFragment

[JEE Main 2024, 04 Apr (Shift 2)]

a

S cm² mol⁻³ᐟ² L¹ᐟ²

b

S cm mol⁻¹ᐟ² L¹ᐟ²

c

S cm² mol⁻³ᐟ² L

d

S cm² mol⁻³ᐟ² L⁻¹ᐟ²

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Q19
PYQ

For a strong electrolyte, a plot of molar conductivity against \({\text{(concentration)}}^{1/2}\) is a straight line, with a negative slope, the correct unit for the slope isEndFragment

[JEE Main 2024, 04 Apr (Shift 2)]

a

S cm² mol⁻³ᐟ² L¹ᐟ²

b

S cm mol⁻¹ᐟ² L¹ᐟ²

c

S cm² mol⁻³ᐟ² L

d

S cm² mol⁻³ᐟ² L⁻¹ᐟ²

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Q20
PYQ

\({\mathrm{E}}_{{\mathrm{Cr}}_{2}{\mathrm{O}}_{7}^{2-}/{\mathrm{Cr}}^{3+}}^{\mathrm{o}}=1.33\mathrm{V}{\mathrm{E}}_{{\mathrm{Cl}}_{2}/{\mathrm{Cl}}^{-}}^{\mathrm{o}}=1.36\mathrm{V}\\ {\mathrm{E}}_{{\mathrm{MnO}}_{4}^{-}/{\mathrm{Mn}}^{2+}}^{\mathrm{o}}=1.51\mathrm{V}{\mathrm{E}}_{{\mathrm{Cr}}^{3+}/\mathrm{Cr}}^{\mathrm{o}}=-0.74\mathrm{V}\)

Mark the strongest reducing agent.
(Memory Based JEE Mains 24/01/2025 ,Shift -2)

a

\({\mathrm{Cl}}^{-}\)

b

Cr

c

\({\mathrm{Cr}}^{3+}\)

d

\({\mathrm{Mn}}^{2+}\)

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Q21
PYQ

\({\mathrm{Fe}}^{2+}+{\mathrm{Ag}}^{+}\to {\mathrm{Fe}}^{3+}+\mathrm{Ag};{\mathrm{E}}_{\mathrm{net}}^{\mathrm{o}}\mathrm{______}?\\ {\mathrm{Ag}}^{+}+{\mathrm{e}}^{-}\to \mathrm{Ag};{\mathrm{E}}^{\mathrm{o}}=\mathrm{x}\\ {\mathrm{Fe}}^{2+}+2{\mathrm{e}}^{-}\to \mathrm{Fe};{\mathrm{E}}^{\mathrm{o}}=\mathrm{y}\\ {\mathrm{Fe}}^{3+}+3{\mathrm{e}}^{-}\to \mathrm{Fe};{\mathrm{E}}^{\mathrm{o}}=\mathrm{z}\\ \mathrm{The}\mathrm{value}\mathrm{of}{\mathrm{E}}_{\mathrm{net}}^{\mathrm{o}}=?\)

(Memory Based 24/ 01/25 Shift-1 )

a

x + y- z

b

x + 3y- 2z

c

y- 2x

d

x -3z+2y

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Q22
PYQ

For a \(Mg\left|M{g}^{2+}(aq)\right|\left|A{g}^{+}(aq)\right|Ag\) the correct Nernst Equation is

[JEE Main 2025, 29 Jan (Shift 1)]

a

\({E}_{\text{cell }}={E}_{\text{cell }}^{o}+\frac{RT}{2F}\ln \frac{{\left[A{g}^{+}\right]}^{2}}{\left[M{g}^{2+}\right]}\)

b

\({E}_{\text{cell }}={E}_{\text{cell }}^{o}-\frac{RT}{2F}\ln \frac{\left[A{g}^{+}\right]}{\left[M{g}^{2+}\right]}\)

c

\({E}_{\text{cell }}={E}_{\text{cell }}^{o}-\frac{RT}{2F}\ln \frac{\left[M{g}^{2+}\right]}{\left[A{g}^{+}\right]}\)

d

\({E}_{\text{cell }}={E}_{\text{cell }}^{o}-\frac{RT}{2F}\ln \frac{{\left[A{g}^{+}\right]}^{2}}{\left[M{g}^{2+}\right]}\)

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Q23
PYQ

On charging the lead storage battery, the oxidation state of lead changes from \({x}_{1}\) to \({y}_{1}\) at the anode and from \({x}_{2}\) to \({y}_{2}\) at the cathode. The values of \({\mathrm{x}}_{1},{\mathrm{y}}_{1},{\mathrm{x}}_{2},{\mathrm{y}}_{2}\) are respectively

[JEE Main 2025, 4 Apr (Shift 1)]

a

+4,+2,0,+2

b

+2,0,+2,+4

c

0,+2,+4,+2

d

+2,0,0,+4

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Q24
PYQ

One of the commonly used electrode is calomel electrode. Under which of the following categories, calomel electrode comes?

[JEE Main 2024, 04 Apr (Shift 1)]

a

Metal ion - Metal electrodes

b

Oxidation - Reduction electrodes

c

Metal - insoluble salt - Anion electrodes

d

Gas - ion electrodes

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Q25
PYQ

One of the commonly used electrode is calomel electrode. Under which of the following categories, calomel electrode comes?

[JEE Main 2024, 04 Apr (Shift 1)]

a

Metal ion - Metal electrodes

b

Oxidation - Reduction electrodes

c

Metal - insoluble salt - Anion electrodes

d

Gas - ion electrodes

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Q26
PYQ

\({\mathrm{Fe}}^{2+}+{\mathrm{Ag}}^{+}\to {\mathrm{Fe}}^{3+}+\mathrm{Ag};{\mathrm{E}}_{\mathrm{net}}^{\mathrm{o}}\mathrm{______}?\\ {\mathrm{Ag}}^{+}+{\mathrm{e}}^{-}\to \mathrm{Ag};{\mathrm{E}}^{\mathrm{o}}=\mathrm{x}\\ {\mathrm{Fe}}^{2+}+2{\mathrm{e}}^{-}\to \mathrm{Fe};{\mathrm{E}}^{\mathrm{o}}=\mathrm{y}\\ {\mathrm{Fe}}^{3+}+3{\mathrm{e}}^{-}\to \mathrm{Fe};{\mathrm{E}}^{\mathrm{o}}=\mathrm{z}\\ \mathrm{The}\mathrm{value}\mathrm{of}{\mathrm{E}}_{\mathrm{net}}^{\mathrm{o}}=?\)

(Memory Based 24/ 01/25 Shift-1 )

a

x + y- z

b

x + 3y- 2z

c

y- 2x

d

x -3z+2y

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Q27
PYQ

Which of the following ions is the strongest oxidizing agent (Memory based 29 Jan /2025 morning shift )

\(\mathrm{Given}:{{\mathrm{E}}^{0}}_{{\mathrm{Al}}^{3+}/\mathrm{Al}}=-2.7\mathrm{V}\\ {{\mathrm{E}}^{0}}_{{\mathrm{Cu}}^{2+}/\mathrm{Cu}}=0.34\mathrm{V}\\ {{\mathrm{E}}^{0}}_{{\mathrm{Pb}}^{4+}/{\mathrm{Pb}}^{2+}}=1.8\mathrm{V}\\ {{\mathrm{E}}^{0}}_{{\mathrm{Ti}}^{3+}/\mathrm{Ti}}=-1.21\mathrm{V}\)

a

\({\mathrm{Al}}^{3+}\)

b

\(C{u}^{2+}\)

c

\(P{b}^{4+}\)

d

\(T{i}^{3+}\)

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Q28
PYQ

One of the commonly used electrode is calomel electrode. Under which of the following categories, calomel electrode comes?

[JEE Main 2024, 4 Apr (Shift 1)]

a

Metal ion - Metal electrodes

b

Oxidation - Reduction electrodes

c

Metal - Insoluble Salt - Anion electrodes

d

Gas - Ion electrodes

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Q29
PYQ

Which of the following statements is not correct about rusting of iron?

a

Rusting of iron is envisaged as setting up of electrochemical cell on the surface of iron object.

b

Coating of iron surface by tin prevents rusting, even if the tin coating is peeling off.

c

When \(\mathrm{pH}\) lies above 9 or 10, rusting of iron does not take place.

d

Dissolved acidic oxides \(\mathrm{SO}_{2}, \mathrm{NO}_{2}\) in water act as catalyst in the process of rusting.

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Q30
PYQ

Which of the following statements is not correct about rusting of iron?

a

Rusting of iron is envisaged as setting up of electrochemical cell on the surface of iron object.

b

Coating of iron surface by tin prevents rusting, even if the tin coating is peeling off.

c

When \(\mathrm{pH}\) lies above 9 or 10, rusting of iron does not take place.

d

Dissolved acidic oxides \(\mathrm{SO}_{2}, \mathrm{NO}_{2}\) in water act as catalyst in the process of rusting.

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Q31
PYQ

Which of the following statements is not correct about rusting of iron?

[JEE Main 2024, 27 Jan (Shift 2)]

a

Rusting of iron is envisaged as setting up of electrochemical cell on the surface of iron object.

b

Coating of iron surface by tin prevents rusting, even if the tin coating is peeling off.

c

When \(\mathrm{pH}\) lies above 9 or 10, rusting of iron does not take place.

d

Dissolved acidic oxides \(\mathrm{SO}_{2}, \mathrm{NO}_{2}\) in water act as catalyst in the process of rusting.

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Q32
PYQ

The emf of cell \(Tl\left|\underset{\text{(0.001M)}}{{\text{Tl}}^{\text{+}}}\right|\left|\underset{\text{(0.01M)}}{{\text{Cu}}^{\text{2+}}}\right|\text{Cu is }0.83V\text{ at }298\text{K}.\) It could be increased by :

[JEE Main 2024, 08 Apr (Shift 2)]

a

decreasing concentration of both \(Tl ^{+}\)and \(Cu ^{2+}\) ions

b

increasing concentration of \(Cu ^{2+}\) ions

c

increasing concentration of both \(Tl ^{+}\)and \(Cu ^{2+}\) ions

d

increasing concentration of \(Tl ^{+}\)ions

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Q33
PYQ

The emf of cell \(Tl\left|\underset{\text{(0.001M)}}{{\text{Tl}}^{\text{+}}}\right|\left|\underset{\text{(0.01M)}}{{\text{Cu}}^{\text{2+}}}\right|\text{Cu is }0.83V\text{ at }298\text{K}.\) It could be increased by :

[JEE Main 2024, 08 Apr (Shift 2)]

a

decreasing concentration of both \(Tl ^{+}\)and \(Cu ^{2+}\) ions

b

increasing concentration of \(Cu ^{2+}\) ions

c

increasing concentration of both \(Tl ^{+}\)and \(Cu ^{2+}\) ions

d

increasing concentration of \(Tl ^{+}\)ions

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Q34
PYQ

Identify the factor from the following that does not affect electolytic conductance of a solution.

a

The nature of the electrolyte added

b

The nature of the electrode used

c

The nature of solvent used

d

Concentration of the electrolyte

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Q35
PYQ

Based on the data given below :

\({E}_{C{r}_{2}{O}_{7}^{2-}/C{r}^{3+}}^{0}=1.33V{E}_{C{l}_{2}/C{l}^{(-)}}^{0}=1.36V\\ {E}_{Mn{O}_{4}^{-}/M{n}^{2+}}^{0}=1.51V{E}_{C{r}^{3+}/Cr}^{0}=-0.74V\)
the strongest reducing agent is

[JEE Main 2025, 24 Jan (Shift 2)]

a

\(C{l}^{-}\)

b

\(Mn{O}_{4}^{-}\)

c

Cr

d

\(M{n}^{2+}\)

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Q36
PYQ

What is the correct Nernst equation representation for the following cell reaction? (Memory based 29 Jan /2025 morning shift )

\(\mathrm{Mg}(\mathrm{s})\to {\mathrm{Mg}}^{2+}+2{\mathrm{e}}^{-}\\ {\mathrm{Ag}}^{+}+{\mathrm{e}}^{-}\to \mathrm{Ag}(\mathrm{s})\)

a

\({\mathrm{E}}_{\mathrm{cell}}={{\mathrm{E}}^{0}}_{\mathrm{cell}}-\frac{\mathrm{RT}}{\mathrm{nF}}\ln \frac{\left[{\mathrm{Mg}}^{2+}\right]}{{\left[{\mathrm{Ag}}^{+}\right]}^{2}}\)

b

\({\mathrm{E}}_{\mathrm{cell}}={{\mathrm{E}}^{0}}_{\mathrm{cell}}-\frac{\mathrm{RT}}{\mathrm{nF}}\ln \frac{{\left[{\mathrm{Ag}}^{+}\right]}^{2}}{\left[{\mathrm{Mg}}^{2+}\right]}\)

c

\({\mathrm{E}}_{\mathrm{cell}}={{\mathrm{E}}^{0}}_{\mathrm{cell}}+\frac{\mathrm{RT}}{\mathrm{nF}}\ln \frac{\left[{\mathrm{Mg}}^{2+}\right]}{\left[{\mathrm{Ag}}^{+}\right]}\)

d

\({\mathrm{E}}_{\mathrm{cell}}={{\mathrm{E}}^{0}}_{\mathrm{cell}}+\frac{\mathrm{RT}}{\mathrm{nF}}\ln \frac{\left[{\mathrm{Ag}}^{+}\right]}{\left[{\mathrm{Mg}}^{2+}\right]}\)

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Q37
PYQ

Which of the following electrolyte can be used to obtain \({\mathrm{H}}_{2}{\mathrm{S}}_{2}{\mathrm{O}}_{8}\) by the process of electrolysis?

[JEE Main 2025, 22 Jan (Shift 1)]

a

Dilute solution of sodium sulphate

b

Concentrated solution of sulphuric acid

c

Dilute solution of sulphuric acid

d

Acidified dilute solution of sodium sulphate

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Q38
PYQ

The quantity of silver deposited when one coulomb charge is passed through \(AgN{O}_{3}\) solution

[JEE Main 2024, 05 Apr (Shift 2)]

a

0.1 g atom of silver

b

1 chemical equivalent of silver

c

1 g of silver

d

1 electrochemical equivalent of silver

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Q39
PYQ

The quantity of silver deposited when one coulomb charge is passed through \(AgN{O}_{3}\) solution

[JEE Main 2024, 05 Apr (Shift 2)]

a

0.1 g atom of silver

b

1 chemical equivalent of silver

c

1 g of silver

d

1 electrochemical equivalent of silver

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Q40
PYQ

The reaction at cathode in the cells commonly used in clocks involves

[JEE Main 2024, 05 Apr (Shift 1)]

a

oxidation of Mn from +3 to +4

b

reduction of Mn from +7 to +2

c

oxidation of Mn from +2 to +7

d

reduction of Mn from +4 to +3

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Q41
PYQ

The reaction at cathode in the cells commonly used in clocks involves

[JEE Main 2024, 05 Apr (Shift 1)]

a

oxidation of Mn from +3 to +4

b

reduction of Mn from +7 to +2

c

oxidation of Mn from +2 to +7

d

reduction of Mn from +4 to +3

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Q42
PYQ

A solution of aluminium chloride is electrolysed for 30 minutes using a current of 2 A . The amount of the aluminium deposited at the cathode is ________.
[Given : molar mass of aluminium and chlorine are \(27gmo{l}^{-1}\) and \(35.5gmo{l}^{-1}\) respectively]

[JEE Main 2025, 22 Jan (Shift 1)]

a

660 g

b

0.441 g

c

0.336 g

d

1.007 g

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Q43
PYQ

For the given cell

\(F{e}^{2+}{}_{(aq)}+A{g}^{+}{}_{(aq)}\to F{e}^{3+}{}_{(aq)}+A{g}_{(s)}\)

The standard cell potential of the above reaction is

Given

\(A{g}^{+}+{e}^{-}\to AgE^\circ =xV\)

\(F{e}^{2+}+2{e}^{-}\to FeE^\circ =yV\)

\(F{e}^{3+}+3{e}^{-}\to Fe{E}^{^\circ }=zV\)

[JEE Main 2025, 24 Jan (Shift 1)]

a

x + y – z

b

y – 2x

c

x + 2y

d

x + 2y – 3z

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Q44
PYQ

Consider the following half cell reaction
\({\mathrm{Cr}}_{2}{\mathrm{O}}_{7}^{2-}(\mathrm{aq})+6{\mathrm{e}}^{-}+14{\mathrm{H}}^{+}(\mathrm{aq})\to 2{\mathrm{Cr}}^{3+}(\mathrm{aq})+7{\mathrm{H}}_{2}\mathrm{O}(\mathrm{l})\)
The reaction was conducted with the ratio of \(\frac{{\left[{\mathrm{Cr}}^{3+}\right]}^{2}}{\left[{\mathrm{Cr}}_{2}{\mathrm{O}}_{7}^{2-}\right]}={10}^{-6}\). The pH value at which the EMF of the half cell will become zero is _______ . (nearest integer value)
\([\)Given : standard half cell reduction potential

\(\left.{\mathrm{E}}_{{\mathrm{Cr}}_{2}{\mathrm{O}}_{7}^{2-},{\mathrm{H}}^{+}/{\mathrm{Cr}}^{3+}}^{\mathrm{o}}=1.33\mathrm{V},\frac{2.303\mathrm{RT}}{\mathrm{F}}=0.059\mathrm{V}\right]\)

[JEE Main 2025, 8 Apr (Shift 1)]

a

10

b

15

c

14

d

12

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Q45
PYQ

The standard reduction potential values of some of the p-block ions are given below. Predict the one with the strongest oxidising capacity

[JEE Main 2025, 29 Jan (Shift 1)]

a

\({{E}^{⊖}}_{{\mathrm{Sn}}^{4+}/{\mathrm{Sn}}^{2+}}=+1.15\mathrm{V}\)

b

\({{E}^{⊖}}_{{\mathrm{Pb}}^{4+}/{\mathrm{Pb}}^{2+}}=+1.67\mathrm{V}\)

c

\({\mathrm{E}}_{{\mathrm{Tl}}^{3+}/\mathrm{Tl}}^{⊖}=+1.26\mathrm{V}\)

d

\({E}_{A{l}^{3+}/Al}^{⊖}=-1.66V\)

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Q46
PYQ

The standard cell potential \(\left({\mathrm{E}}_{\text{cell }}^{⊖}\right)\) of a fuel cell based on the oxidation of methanol in air that has been used to power television relay station is measured as \(1.21V\) . The standard half cell reduction potential for \({\mathrm{O}}_{2}\left({\mathrm{E}}_{{\mathrm{O}}_{2}/{\mathrm{H}}_{2}\mathrm{O}}^{\mathrm{O}}\right)\) is \(1.229V\).Choose the correct statement:

[JEE Main 2025, 3 Apr (Shift 2)]

a

The standard half cell reduction potential for the reduction of \({\mathrm{CO}}_{2}\left({\mathrm{E}}_{{\mathrm{CO}}_{2}/{\mathrm{CH}}_{3}\mathrm{OH}}^{o}\right)\) is \(19\) mV

b

Oxygen is formed at the anode.

c

Reactants are fed at one go to each electrode.

d

Reduction of methanol takes place at the cathode.

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Q47
PYQ

Which of the following gives predominantly \({\mathrm{O}}_{2}\) on electrolysis among the following?

A) Aq. \({\mathrm{AgNO}}_{3}\) (Pt electrodes)

B) Aq. \({\mathrm{AgNO}}_{3}\) (Ag electrodes)

C) Conc.\({\mathrm{H}}_{2}{\mathrm{SO}}_{4}\) (Pt electrodes)

D) Dilute \({\mathrm{H}}_{2}{\mathrm{SO}}_{4}\)(Ag electrodes)

Memory Based Question 29/Jan/25 Evening shift

a

AB

b

BC

c

ABC

d

AD

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Q48
PYQ

Given below are two statements

Statement(I): Corrosion is an electrochemical phenomenon in which pure metal acts as an anode, impure metal as a cathode.

Statement(II): The rate of corrosion is more in alkaline medium than in acidic medium

In the light of above statements, choose the correct answer from options given below

[JEE Main 2025, 22 Jan (Shift 2)]

a

Statement-I is false but statement-II is true

b

Statement-I is true but statement-II is false

c

Both statement-I and statement-II are true

d

Both statement-I and statement-II are false

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Q49
PYQ

How can an electrochemical cell be converted into an electrolytic cell?

[JEE Main 2024, 6 Apr (Shift 2)]

a

Applying an external opposite potential greater than \({\mathrm{E}}_{\mathrm{cell}}^{\mathrm{o}}\)

b

Reversing the flow of ions in salt bridge

c

Applying an external opposite potential lower than \(E _{\text {cell }}^0\)

d

Exchanging the electrodes at anode and cathode.

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Q50
PYQ

Fuel cell, using hydrogen and oxygen as fuels,
A. has been used in spaceship
B. has as efficiency of \(40\%\) to produce electricity
C. uses aluminum as catalysts
D. is eco-friendly
E. is actually a type of Galvanic cell only

Choose the correct answer from the options given below

[JEE Main 2024, 4 Apr (Shift 2)]

a

A, B, C only

b

A, D, E only

c

A, B, D only

d

A, B, D, E only

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Q51
PYQ

For the given cell

\(F{e}^{2+}{}_{(aq)}+A{g}^{+}{}_{(aq)}\to F{e}^{3+}{}_{(aq)}+A{g}_{(s)}\)

The standard cell potential of the above reaction is

Given

\(A{g}^{+}+{e}^{-}\to Ag{E}^{\theta }=xV\)

\(F{e}^{2+}+2{e}^{-}\to Fe{E}^{\theta }=yV\)

\(F{e}^{3+}+3{e}^{-}\to Fe{E}^{\theta }=zV\)

a

x + y – z

b

y – 2x

c

x + 2y

d

x + 2y – 3z

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Q52
PYQ

For a \(Mg\left|M{g}^{2+}(aq)\right|\left|A{g}^{+}(aq)\right|Ag\) the correct Nernst Equation is

[JEE Main 2025, 29 Jan (Shift 1)]

a

\({E}_{\text{cell }}={E}_{\text{cell }}^{o}+\frac{RT}{2F}\ln \frac{{\left[A{g}^{+}\right]}^{2}}{\left[M{g}^{2+}\right]}\)

b

\({E}_{\text{cell }}={E}_{\text{cell }}^{o}-\frac{RT}{2F}\ln \frac{\left[A{g}^{+}\right]}{\left[M{g}^{2+}\right]}\)

c

\({E}_{\text{cell }}={E}_{\text{cell }}^{o}-\frac{RT}{2F}\ln \frac{\left[M{g}^{2+}\right]}{\left[A{g}^{+}\right]}\)

d

\({E}_{\text{cell }}={E}_{\text{cell }}^{o}-\frac{RT}{2F}\ln \frac{{\left[A{g}^{+}\right]}^{2}}{\left[M{g}^{2+}\right]}\)

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Q53
PYQ

Consider the following reduction process:

\({\mathrm{Al}}^{3+}+3{\mathrm{e}}^{−}\overset{}{\to }\mathrm{Al}(\mathrm{s}),\text{  }\mathrm{E}^\circ =−1.66\text{​​}V\)

\({\mathrm{Fe}}^{3+}+{\mathrm{e}}^{−}\overset{}{\to }{\mathrm{Fe}}^{2+},\text{  }\mathrm{E}^\circ =+0.77\mathrm{V}\)

\({\mathrm{Co}}^{3+}+{\mathrm{e}}^{−}\overset{}{\to }{\mathrm{Co}}^{2+},\text{ }\mathrm{E}^\circ =+1.81\mathrm{V}\)

\({\mathrm{Cr}}^{3+}+3{\mathrm{e}}^{−}\overset{}{\to }\mathrm{Cr}(\mathrm{s}),\text{  }\mathrm{E}^\circ =−0.74\mathrm{V}\)

The tendency to act as reducing agent decreases in the order

[JEE Main 2026, 22 Jan (Shift 2)]

a

Al > Cr > Fe2+ > Co2+

b

Al > Cr > Co2+ > Fe2+

c

Al > Fe2+ > Cr > Co2+

d

Cr > Fe2+ > Al > Co2+

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Q54
PYQ

Given below are two statements :
\(1\) M aqueous solution of each of \(\mathrm{Cu}{\left({\mathrm{NO}}_{3}\right)}_{2}\), \({\mathrm{AgNO}}_{3},{\mathrm{Hg}}_{2}{\left({\mathrm{NO}}_{3}\right)}_{2};\mathrm{Mg}{\left({\mathrm{NO}}_{3}\right)}_{2}\) are electrolysed using inert electrodes
Given : \({\mathrm{E}}_{{\mathrm{Ag}}^{+}/\mathrm{Ag}}^{\mathrm{o}}=0.80\mathrm{V},{\mathrm{E}}_{{\mathrm{Hg}}_{2}^{2+}/\mathrm{Hg}}^{\mathrm{o}}=0.79\mathrm{V}\), \({\mathrm{E}}_{{\mathrm{Cu}}^{2+}/\mathrm{Cu}}^{\mathrm{o}}=0.24\mathrm{V}\text{ and }{\mathrm{E}}_{{\mathrm{Mg}}^{2+}/\mathrm{Mg}}^{\mathrm{o}}=-2.37\mathrm{V}\)
Statement (I) : With increasing voltage, the sequence of deposition of metals on the cathode will be \(\mathrm{Ag},\mathrm{Hg}\) and \(\mathrm{Cu}\)
Statement (II) : Magnesium will not be deposited at cathode instead oxygen gas will be evolved at the cathode.
In the light of the above statement, choose the most appropriate answer from the options given below

[JEE Main 2025, 7 Apr (Shift 2)]

a

Both statement I and statement II are incorrect

b

Statement I is correct but statement II is incorrect

c

Both statement I and statement II are correct

d

Statement I is incorrect but statement II is correct

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Q55
PYQ

In the given electrochemical cell, \(\mathrm{Ag}(\mathrm{s})|\mathrm{AgCl}(\mathrm{s})|{\mathrm{FeCl}}_{2}(\mathrm{aq}),{\mathrm{FeCl}}_{3}(\mathrm{aq})∣\mathrm{Pt}(\mathrm{s})\)

at 298 K, the cell potential (Ecell) will increase when:

(A) Concentration of Fe2+ is increased.

(B) Concentration of Fe3+ is decreased.

(C) Concentration of Fe2+ is decreased.

(D) Concentration of Fe3+ is increased.

(E) Concentration of Clis increased.

Choose the correct answer from the options given below

[JEE Main 2026, 23 Jan (Shift 1)]

a

A and E Only

b

A and B Only

c

B Only

d

C, D and E Only

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Q56
PYQ

Correct order of limiting molar conductivity for cations in water at \(298K\) is

[JEE Main 2025, 3 Apr (Shift 1)]

a

\({\mathrm{H}}^{+}>{\mathrm{Na}}^{+}>{\mathrm{K}}^{+}>{\mathrm{Ca}}^{2+}>{\mathrm{Mg}}^{2+}\)

b

\({\mathrm{H}}^{+}>{\mathrm{Ca}}^{2+}>{\mathrm{Mg}}^{2+}>{\mathrm{K}}^{+}>{\mathrm{Na}}^{+}\)

c

\({\mathrm{Mg}}^{2+}>{\mathrm{H}}^{+}>{\mathrm{Ca}}^{2+}>{\mathrm{K}}^{+}>{\mathrm{Na}}^{+}\)

d

\({\mathrm{H}}^{+}>{\mathrm{Na}}^{+}>{\mathrm{Ca}}^{2+}>{\mathrm{Mg}}^{2+}>{\mathrm{K}}^{+}\)

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Q57
PYQ

The standard cell potential \(\left({\mathrm{E}}_{\text{cell }}^{⊖}\right)\) of a fuel cell based on the oxidation of methanol in air that has been used to power television relay station is measured as \(1.21V\) . The standard half cell reduction potential for \({\mathrm{O}}_{2}\left({\mathrm{E}}_{{\mathrm{O}}_{2}/{\mathrm{H}}_{2}\mathrm{O}}^{\mathrm{O}}\right)\) is \(1.229V\).Choose the correct statement:

[JEE Main 2025, 3 Apr (Shift 2)]

a

The standard half cell reduction potential for the reduction of \({\mathrm{CO}}_{2}\left({\mathrm{E}}_{{\mathrm{CO}}_{2}/{\mathrm{CH}}_{3}\mathrm{OH}}^{o}\right)\) is \(19\) mV

b

Oxygen is formed at the anode.

c

Reactants are fed at one go to each electrode.

d

Reduction of methanol takes place at the cathode.

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Q58
PYQ

Based on the data given below :

\({E}_{C{r}_{2}{O}_{7}^{2-}/C{r}^{3+}}^{0}=1.33V{E}_{C{l}_{2}/C{l}^{(-)}}^{0}=1.36V\\ {E}_{Mn{O}_{4}^{-}/M{n}^{2+}}^{0}=1.51V{E}_{C{r}^{3+}/Cr}^{0}=-0.74V\)
the strongest reducing agent is

[JEE Main 2025, 24 Jan (Shift 2)]

a

\(C{l}^{-}\)

b

\(Mn{O}_{4}^{-}\)

c

Cr

d

\(M{n}^{2+}\)

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Q59
PYQ

In the given electrochemical cell, \(\mathrm{Ag}(\mathrm{s})|\mathrm{AgCl}(\mathrm{s})|{\mathrm{FeCl}}_{2}(\mathrm{aq}),{\mathrm{FeCl}}_{3}(\mathrm{aq})∣\mathrm{Pt}(\mathrm{s})\)

at 298 K, the cell potential (Ecell) will increase when:

(A) Concentration of Fe2+ is increased.

(B) Concentration of Fe3+ is decreased.

(C) Concentration of Fe2+ is decreased.

(D) Concentration of Fe3+ is increased.

(E) Concentration of Clis increased.

Choose the correct answer from the options given below

[JEE Main 2026, 23 Jan (Shift 1)]

a

A and E Only

b

A and B Only

c

B Only

d

C, D and E Only

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Q60
PYQ

Which out of the following is a correct equation to show change in molar conductivity with respect to concentration for a weak electrolyte, if the symbols carry their usual meaning

[JEE Main 2024, 09 Apr (Shift 2)]

a

\({\Lambda }_{\mathrm{m}}^{2}\mathrm{C}-{\mathrm{K}}_{\mathrm{a}}{\Lambda }_{\mathrm{m}}^{∘2}+{\mathrm{K}}_{\mathrm{a}}{\Lambda }_{\mathrm{m}}{\Lambda }_{\mathrm{m}}^\circ =0\)

b

\({\Lambda }_{\mathrm{m}}-{\Lambda }_{\mathrm{m}}^\circ +{\mathrm{AC}}^{\frac{1}{2}}=0\)

c

\({\Lambda }_{\mathrm{m}}-{\Lambda }_{\mathrm{m}}^\circ -{\mathrm{AC}}^{\frac{1}{2}}=0\)

d

\({\Lambda }^{2}{}_{\mathrm{m}}\mathrm{C}+{\mathrm{K}}_{\mathrm{a}}{\Lambda }_{\mathrm{m}}^{{∘}^{2}}-{\mathrm{K}}_{\mathrm{a}}{\Lambda }_{\mathrm{m}}{\Lambda }_{\mathrm{m}}^\circ =0\)

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Q61
PYQ

Which out of the following is a correct equation to show change in molar conductivity with respect to concentration for a weak electrolyte, if the symbols carry their usual meaning

[JEE Main 2024, 09 Apr (Shift 2)]

a

\({\Lambda }_{\mathrm{m}}^{2}\mathrm{C}-{\mathrm{K}}_{\mathrm{a}}{\Lambda }_{\mathrm{m}}^{∘2}+{\mathrm{K}}_{\mathrm{a}}{\Lambda }_{\mathrm{m}}{\Lambda }_{\mathrm{m}}^\circ =0\)

b

\({\Lambda }_{\mathrm{m}}-{\Lambda }_{\mathrm{m}}^\circ +{\mathrm{AC}}^{\frac{1}{2}}=0\)

c

\({\Lambda }_{\mathrm{m}}-{\Lambda }_{\mathrm{m}}^\circ -{\mathrm{AC}}^{\frac{1}{2}}=0\)

d

\({\Lambda }^{2}{}_{\mathrm{m}}\mathrm{C}+{\mathrm{K}}_{\mathrm{a}}{\Lambda }_{\mathrm{m}}^{{∘}^{2}}-{\mathrm{K}}_{\mathrm{a}}{\Lambda }_{\mathrm{m}}{\Lambda }_{\mathrm{m}}^\circ =0\)

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Q62
PYQ

How can an electrochemical cell be converted into an electrolytic cell

[JEE Main 2024, 6 Apr (Shift 2)]

a

Reversing the flow of ions in salt bridge

b

Applying an external opposite potential greater than \({\mathrm{E}}_{\mathrm{cell}}^{\mathrm{o}}\)

c

Exchanging the electrodes at anode and cathode.

d

Applying an external opposite potential lower than \(E _{\text {cell }}^0\)

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Q63
PYQ

Identify the factor from the following that does not affect electrolytic conductance of a solution.

[JEE Main 2024, 31 Jan (Shift 1)]

a

Concentration of the electrolyte.

b

The nature of the electrode used.

c

The nature of solvent used.

d

The nature of the electrolyte added.

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Q64
PYQ

Consider the following

\({\mathrm{E}}^{0}\mathrm{Value}\mathrm{for}\mathrm{the}\mathrm{given}\mathrm{half}\mathrm{cell}\\ {{\mathrm{E}}^{0}}_{{\mathrm{Ag}}^{+}/\mathrm{Ag}}=0.8\mathrm{V},{{\mathrm{E}}^{0}}_{{\mathrm{Zn}}^{2+}/\mathrm{Zn}}=-0.76\mathrm{V}\\ {{\mathrm{E}}^{0}}_{{\mathrm{Cu}}^{2+}/\mathrm{Cu}}=0.34\mathrm{V}{{\mathrm{E}}^{0}}_{{\mathrm{Mg}}^{2+}/\mathrm{Mg}}=-2.35\mathrm{V}\\ \mathrm{Then}\mathrm{which}\mathrm{of}\mathrm{the}\mathrm{following}\mathrm{will}\mathrm{have}\mathrm{the}\mathrm{most}\mathrm{negative}\mathrm{value}\mathrm{of}∆{\mathrm{G}}^{0}?\)

(Memory Based JEE Mains 23/01/2025 ,Shift -2)

a

\(Zn|Z{n}^{2+}∥C{u}^{2+}|Cu\)

b

\(Mg|M{g}^{2+}∥A{g}^{+}|Ag\)

c

\(Mg|M{g}^{2+}∥Z{n}^{2+}|Zn\)

d

\(Cu|C{u}^{2+}∥A{g}^{+}|Ag\)

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Q65
PYQ

Given below are two statements

Statement(I): Corrosion is an electrochemical phenomenon in which pure metal acts as an anode, impure metal as a cathode.

Statement(II): The rate of corrosion is more in alkaline medium than in acidic medium

In the light of above statements, choose the correct answer from options given below

[JEE Main 2025, 22 Jan (Shift 2)]

a

Statement-I is false but statement-II is true

b

Statement-I is true but statement-II is false

c

Both statement-I and statement-II are true

d

Both statement-I and statement-II are false

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Q66
PYQ

\(0.2\%(\mathrm{w}/\mathrm{v})\) solution of \(\mathrm{NaOH}\) is measured to have resistivity \(870.0\mathrm{m}\Omega \mathrm{m}\). The molar conductivity of the solution will be ________ \(\times {10}^{2}\mathrm{mS}{\mathrm{dm}}^{2}{\mathrm{mol}}^{-1}\). (Nearest integer)

[JEE Main 2025, 2 Apr (Shift 2)]

a

23

b

25

c

27

d

29

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Q67
PYQ

In an electrochemical cell, dichromate ions in aqueous acidic medium are reduced to \({\mathrm{Cr}}^{3+}\). The current (in amperes) that flows through the cell for 48.25 minutes to produce 1 mole of \({\mathrm{Cr}}^{3+}\) is

Use: 1 Faraday \(=96500{\mathrm{Cmol}}^{-1}\)

a

100

b

150

c

200

d

250

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Q68
PYQ

Given below are two statements :
Statement I : Mohr's salt is composed of only three types of ions-ferrous, ammonium and sulphate.
Statement II : If the molar conductance at infinite dilution of ferrous, ammonium and sulphate ions are \({\mathrm{x}}_{1},{\mathrm{x}}_{2}\) and \({\mathrm{x}}_{3}\mathrm{S}{\mathrm{cm}}^{2}{\mathrm{mol}}^{-1}\), respectively then the molar conductance for Mohr's salt solution at infinite dilution would be given by \({\mathrm{x}}_{1}+{\mathrm{x}}_{2}+2{\mathrm{x}}_{3}\)
In the light of the given statements, choose the correct answer from the options given below

[JEE Main 2025, 7 Apr (Shift 1)]

a

Both statements I and Statement II is false

b

Statement I is false but Statement II is true

c

Statement I is true but Statement II are false

d

Both statements I and Statement II are true

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Q69
PYQ

The standard reduction potential values of some of the p-block ions are given below. Predict the one with the strongest oxidising capacity

a

\({{E}^{⊖}}_{{\mathrm{Sn}}^{4+}/{\mathrm{Sn}}^{2+}}=+1.15\mathrm{V}\)

b

\({{E}^{⊖}}_{{\mathrm{Pb}}^{4+}/{\mathrm{Pb}}^{2+}}=+1.67\mathrm{V}\)

c

\({\mathrm{E}}_{{\mathrm{Tl}}^{3+}/\mathrm{Tl}}^{⊖}=+1.26\mathrm{V}\)

d

\({E}_{A{l}^{3+}/Al}^{⊖}=-1.66V\)

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Q70
PYQ

Which of the following has least tendency to liberate \({H}_{2}\) from mineral acids?

a

Cu

b

Mn

c

Ni

d

Zn

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Q71
PYQ

Given below are two statements. Select the correct option (memory based jee mains shift-2 22/01/2025)

Statement-1: In corrosion pure metal acts as anode, the impure metal acts as a cathode

Statement-2: Alkaline medium increases the rate of corrosion more than in acidic medium

a

Statement-1 is correct but statement-2 is incorrect

b

Statement-1 is incorrect but statement-2 is correct

c

Both statements are correct

d

Both statements are incorrect

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Q72
PYQ

Consider the following reduction process:

\({\mathrm{Al}}^{3+}+3{\mathrm{e}}^{−}\overset{}{\to }\mathrm{Al}(\mathrm{s}),\text{  }\mathrm{E}^\circ =−1.66\text{​​}V\)

\({\mathrm{Fe}}^{3+}+{\mathrm{e}}^{−}\overset{}{\to }{\mathrm{Fe}}^{2+},\text{  }\mathrm{E}^\circ =+0.77\mathrm{V}\)

\({\mathrm{Co}}^{3+}+{\mathrm{e}}^{−}\overset{}{\to }{\mathrm{Co}}^{2+},\text{ }\mathrm{E}^\circ =+1.81\mathrm{V}\)

\({\mathrm{Cr}}^{3+}+3{\mathrm{e}}^{−}\overset{}{\to }\mathrm{Cr}(\mathrm{s}),\text{  }\mathrm{E}^\circ =−0.74\mathrm{V}\)

The tendency to act as reducing agent decreases in the order

[JEE Main 2026, 22 Jan (Shift 2)]

a

Al > Cr > Fe2+ > Co2+

b

Al > Cr > Co2+ > Fe2+

c

Al > Fe2+ > Cr > Co2+

d

Cr > Fe2+ > Al > Co2+

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Q73
PYQ

Standard electrode potentials for a few half cells are mentioned below

\({\text{E}}_{C{u}^{2+}/Cu}^{∘}=0.34\text{V},{\text{E}}_{Z{n}^{2+}/Zn}^{∘}=−0.76\text{V}\)

\({\text{E}}_{A{g}^{+}/Ag}^{∘}=0.80\text{V},{\text{E}}_{M{g}^{2+}/Mg}^{∘}=−2.37\text{V}\)

Which one of the following cells give the most negative value of \(∆{\mathrm{G}}^{\mathrm{o}}\)?

[JEE Main 2025, 23 Jan (Shift 2)]

a

\(\mathrm{Zn}|{\mathrm{Zn}}^{2+}\left(1\mathrm{M}\right)||{\mathrm{Mg}}^{2+}\left(1\mathrm{M}\right)|\mathrm{Mg}\)

b

\(\mathrm{Ag}|{\mathrm{Ag}}^{+}\left(1\mathrm{M}\right)||{\mathrm{Mg}}^{2+}\left(1\mathrm{M}\right)|\mathrm{Mg}\)

c

\(\mathrm{Zn}|{\mathrm{Zn}}^{2+}\left(1\mathrm{M}\right)||{\mathrm{Ag}}^{+}\left(1\mathrm{M}\right)|\mathrm{Ag}\)

d

\(\mathrm{Cu}|{\mathrm{Cu}}^{2+}\left(1\mathrm{M}\right)||{\mathrm{Ag}}^{+}\left(1\mathrm{M}\right)|\mathrm{Ag}\)

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Q74
PYQ

Which of the following ions is the strongest oxidizing agent (Memory based 29 Jan /2025 morning shift )

\(\mathrm{Given}:{{\mathrm{E}}^{0}}_{{\mathrm{Al}}^{3+}/\mathrm{Al}}=-2.7\mathrm{V}\\ {{\mathrm{E}}^{0}}_{{\mathrm{Cu}}^{2+}/\mathrm{Cu}}=0.34\mathrm{V}\\ {{\mathrm{E}}^{0}}_{{\mathrm{Pb}}^{4+}/{\mathrm{Pb}}^{2+}}=1.8\mathrm{V}\\ {{\mathrm{E}}^{0}}_{{\mathrm{Ti}}^{3+}/\mathrm{Ti}}=-1.21\mathrm{V}\)

a

\({\mathrm{Al}}^{3+}\)

b

\(C{u}^{2+}\)

c

\(P{b}^{4+}\)

d

\(T{i}^{3+}\)

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Q75
PYQ

The reaction ;
\(\frac{1}{2}{H}_{2(g)}+AgC{l}_{(s)}\to {H}_{(aq)}^{+}+C{l}_{(aq)}^{-}+A{g}_{(s)}\)
occurs in which of the following galvanic cell :

[JEE Main 2024, 8 Apr (Shift 2)]

a

\(Pt \left| H _{2( g )}\right| HCl _{\text {(soln.) }}\left| AgCl _{( s )}\right| Ag\)

b

\(Pt \left| H _{2( g )}\right| KCl _{(\text {soln. })}\left| AgCl _{( s )}\right| Ag\)

c

\(Ag \left| AgCl _{(\text {s) }}\right| KCl _{\text {(soln.) }}\left| AgNO _{3 \text { (aq.) }}\right| Ag\)

d

\(Pt \left| H _{2( g )}\right| HCl _{(\text {soln.) }}\left| AgNO _{3( aq )}\right| Ag\)

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Q76
PYQ

Which of the following gives predominantly \({\mathrm{O}}_{2}\) on electrolysis among the following?

A) Aq. \({\mathrm{AgNO}}_{3}\) (Pt electrodes)

B) Aq. \({\mathrm{AgNO}}_{3}\) (Ag electrodes)

C) Conc.\({\mathrm{H}}_{2}{\mathrm{SO}}_{4}\) (Pt electrodes)

D) Dilute \({\mathrm{H}}_{2}{\mathrm{SO}}_{4}\)(Ag electrodes)

Memory Based Question 29/Jan/25 Evening shift

a

AB

b

BC

c

ABC

d

AD

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Q77
PYQ

Which of the following has least tendency to liberate \({H}_{2}\) from mineral acids?

a

Cu

b

Mn

c

Ni

d

Zn

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Q78
PYQ

Which of the following electrolyte can be used to obtain \({\mathrm{H}}_{2}{\mathrm{S}}_{2}{\mathrm{O}}_{8}\) by the process of electrolysis?

[JEE Main 2025, 22 Jan (Shift 1)]

a

Dilute solution of sodium sulphate

b

Concentrated solution of sulphuric acid

c

Dilute solution of sulphuric acid

d

Acidified dilute solution of sodium sulphate

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Q79
PYQ

The reaction ;
\(\frac{1}{2}{H}_{2(g)}+AgC{l}_{(s)}\to {H}_{(aq)}^{+}+C{l}_{(aq)}^{-}+A{g}_{(s)}\)
occurs in which of the following galvanic cell :

[JEE Main 2024, 8 Apr (Shift 2)]

a

\(Pt \left| H _{2( g )}\right| HCl _{\text {(soln.) }}\left| AgCl _{( s )}\right| Ag\)

b

\(Pt \left| H _{2( g )}\right| KCl _{(\text {soln. })}\left| AgCl _{( s )}\right| Ag\)

c

\(Ag \left| AgCl _{(\text {s) }}\right| KCl _{\text {(soln.) }}\left| AgNO _{3 \text { (aq.) }}\right| Ag\)

d

\(Pt \left| H _{2( g )}\right| HCl _{(\text {soln.) }}\left| AgNO _{3( aq )}\right| Ag\)

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Q80
PYQ

Electrolysis of 600 mL aqueous solution of NaCl for 5 min changes the pH of the solution to 12 . The current in Amperes used for the given electrolysis is ______ (Nearest integer)

[JEE Main 2025, 28 Jan (Shift 2)]

a

6

b

4

c

2

d

10

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Q81
PYQ

One of the commonly used electrode is calomel electrode. Under which of the following categories, calomel electrode comes?

[JEE Main 2024, 4 Apr (Shift 1)]

a

Metal ion - Metal electrodes

b

Oxidation - Reduction electrodes

c

Metal - Insoluble Salt - Anion electrodes

d

Gas - Ion electrodes

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Q82
PYQ

Reduction potential of ions are given below:

\({\mathrm{ClO}}_{4}^{–}{\mathrm{IO}}_{4}^{–}{\mathrm{BrO}}_{4}^{–}\\ \mathrm{E}^\circ =1.19\mathrm{V}\mathrm{E}^\circ =1.65\mathrm{V}\mathrm{E}^\circ =1.74\mathrm{V}\)

The correct order their oxidizing power is:

[JEE Main 2024, 30 Jan (Shift 2)]

a

\({\mathrm{CIO}}_{4}^{–}>{\mathrm{IO}}_{4}^{–}>{\mathrm{BrO}}_{4}^{–}\)

b

\({\mathrm{BrO}}_{4}^{–}>{\mathrm{IO}}_{4}^{–}>{\mathrm{CIO}}_{4}^{–}\)

c

\({\mathrm{BrO}}_{4}^{–}>{\mathrm{CIO}}_{4}^{–}>{\mathrm{IO}}_{4}^{–}\)

d

\({\mathrm{IO}}_{4}^{–}>{\mathrm{BrO}}_{4}^{–}>{\mathrm{CIO}}_{4}^{–}\)

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Q83
PYQ

What is the correct Nernst equation representation for the following cell reaction? (Memory based 29 Jan /2025 morning shift )

\(\mathrm{Mg}(\mathrm{s})\to {\mathrm{Mg}}^{2+}+2{\mathrm{e}}^{-}\\ {\mathrm{Ag}}^{+}+{\mathrm{e}}^{-}\to \mathrm{Ag}(\mathrm{s})\)

a

\({\mathrm{E}}_{\mathrm{cell}}={{\mathrm{E}}^{0}}_{\mathrm{cell}}-\frac{\mathrm{RT}}{\mathrm{nF}}\ln \frac{\left[{\mathrm{Mg}}^{2+}\right]}{{\left[{\mathrm{Ag}}^{+}\right]}^{2}}\)

b

\({\mathrm{E}}_{\mathrm{cell}}={{\mathrm{E}}^{0}}_{\mathrm{cell}}-\frac{\mathrm{RT}}{\mathrm{nF}}\ln \frac{{\left[{\mathrm{Ag}}^{+}\right]}^{2}}{\left[{\mathrm{Mg}}^{2+}\right]}\)

c

\({\mathrm{E}}_{\mathrm{cell}}={{\mathrm{E}}^{0}}_{\mathrm{cell}}+\frac{\mathrm{RT}}{\mathrm{nF}}\ln \frac{\left[{\mathrm{Mg}}^{2+}\right]}{\left[{\mathrm{Ag}}^{+}\right]}\)

d

\({\mathrm{E}}_{\mathrm{cell}}={{\mathrm{E}}^{0}}_{\mathrm{cell}}+\frac{\mathrm{RT}}{\mathrm{nF}}\ln \frac{\left[{\mathrm{Ag}}^{+}\right]}{\left[{\mathrm{Mg}}^{2+}\right]}\)

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Q84
PYQ

A metal surface of \(100 \mathrm{~cm}^{2}\) area has to be coated with nickel layer of thickness \(0.001 \mathrm{~mm}\). A current of \(2 \mathrm{~A}\) was passed through a solution of \(\mathrm{Ni}\left(\mathrm{NO}_{3}\right)_{2}\) for ' \(x\) ' seconds to coat the desired layer. The value of \(x\) is........................... (Nearest integer)

\(\left(\mathrm{p}_{\mathrm{Ni}}\right.\) (density of Nickel) is \(10{\mathrm{g}\mathrm{mL}}^{-1}\), Molar mass of Nickel is \(60 \mathrm{~gmol}^{-1} \mathrm{~F}=96500 \mathrm{~C} \mathrm{mol}^{-1}\) )

a

161

b

162

c

132

d

164

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Q85
PYQ

The molar conductance of \( \mathrm{NaCl}, \mathrm{HCl} \) and \( \mathrm{CH}_{3} \mathrm{COONa} \) at infinite dilution are \( 126.45 \)\(,\) \( 426.16 \) and \( 91.0 \mathrm{~S} \mathrm{~cm}^{2} \mathrm{~mol}^{-1} \) respectively. The molar conductance of \( \mathrm{CH}_{3} \mathrm{COOH} \) at infinite dilution is:

[NEET 2021]

a

\( 390.71 \mathrm{~S} \mathrm{~cm}^{2} \mathrm{~mol}^{-1} \)

b

\( 698.28 \mathrm{~S} \mathrm{~cm}^{2} \mathrm{~mol}^{-1} \)

c

\( 540.48 \mathrm{~S} \mathrm{~cm}^{2} \mathrm{~mol}^{-1} \)

d

\( 201.28 \mathrm{~S} \mathrm{~cm}^{2} \mathrm{~mol}^{-1} \)

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Q86
PYQ

The photoelectric current from \(\mathrm{Na}\) (work function, \(\mathrm{w}_{\mathrm{o}}=2.3 \mathrm{~eV}\) ) is stopped by the output voltage of the cell
\(\mathrm{Pt}(\mathrm{s}) / \mathrm{H}_{2}\) (g, 1 bar) \(\mid \mathrm{HCl}\) (aq., \(\mathrm{pH}=1\) ) \(|\mathrm{AgCl}(\mathrm{s})| \mathrm{Ag}\) (s)

The \(\mathrm{pH}\) of aq. \(\mathrm{HCl}\) required to stop the photoelectric current from \(\mathrm{K}\left(\mathrm{w}_{o}=2.25 \mathrm{~eV}\right)\), all other conditions remaining the same, is________ \(\times 10^{-2}\) (to the nearest integer).

Given:

\(2.303 \frac{\mathrm{RT}}{\mathrm{F}}=0.06 \mathrm{~V} ; \mathrm{E}_{\mathrm{AgCl}|\mathrm{Ag}| \mathrm{Cl^-}}^{\circ}=0.22 \mathrm{~V}\)

[JEE Main 2020, 3 Sep (Shift 1)]

a

135

b

141

c

150

d

189

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Q87
PYQ

In an electrochemical reaction of lead, at standard temperature, if \(\mathrm{E}_{\left(\mathrm{Pb}^{2+} / \mathrm{Pb}\right)}^{\circ}=\mathrm{m}\) Volt and \(\mathrm{E}_{\left(\mathrm{Pb}^{4+} / \mathrm{Pb}\right)}^{\circ}=\mathrm{n}\) Volt , then the value of \(\mathrm{E}_{\left(\mathrm{Pb}^{2+} / \mathrm{Pb}^{4+}\right)}^{\circ}\) is given by \(\mathrm{m}-\mathrm{xn}\). The value of \(\mathrm{x}\) is ___. (Nearest integer)

[JEE Main 2023, 11 Apr (Shift 1)]

a

2

b

4

c

3

d

1

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Q88
PYQ

Given that the standard potentials \( \left(\mathrm{E}^{\circ}\right) \) of \( \mathrm{Cu}^{2+} / \mathrm{Cu} \) and \( \mathrm{Cu}^{+} / \mathrm{Cu} \) are \( 0.34 \mathrm{~V} \) and \( 0.522 \mathrm{~V} \) respectively, the \( \mathrm{E}^{\circ} \) of \( \mathrm{Cu}^{2+} / \mathrm{Cu}^{+} \)is:

[JEE Main 2020, 7 Jan (Shift 1)]

a

+0.158 V

b

–0.182 V

c

+0.182 V

d

–0.158 V

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Q89
PYQ

Consider the following reaction

\[\mathrm{MnO}_{4}^{-}+8 \mathrm{H}^{+}+5 \mathrm{e}^{-} \rightarrow \mathrm{Mn}^{+2}+4 \mathrm{H}_{2} \mathrm{O}, \mathrm{E}^{\mathrm{o}}=1.51 \mathrm{~V}\]

The quantity of electricity required in Faraday to reduce five moles of \( \mathrm{MnO}_{4}^{-} \)is......

a

25

b

20

c

15

d

10

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Q90
PYQ

Potassium chlorate is prepared by the electrolysis of \(\mathrm{KCl}\) in basic solution as:

\(6 \mathrm{OH}^{-}+\mathrm{Cl}^{-} \rightarrow \mathrm{ClO}_{3}^{-}+3 \mathrm{H}_{2} \mathrm{O}+6 \mathrm{e}^{-}\)

If only \(60 \%\) of the current is utilized in the reaction, the time (rounded off to the nearest hour) required to produce \(10 \mathrm{~g}\) of \(\mathrm{KClO}_{3}\) using a current of \(2 \mathrm{~A}\) is _____.

(Given: \(\mathrm{F}=96,500 \mathrm{C} \mathrm{mol}^{-1}\); molar mass of \(\mathrm{KClO}_{3}=122\) \(\mathrm{g} \mathrm{mol}^{-1}\) )

[JEE Main 2020, 6 Sep (Shift 1)]

a

15

b

14

c

12

d

11

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Q91
PYQ

On electrolysis of dil sulphuric acid using Platinum electrode, the product obtained at anode will be \(:\)

[NEET 2020]

a

Oxygen gas

b

\({\mathrm{H}}_{2}\mathrm{S}\mathrm{gas}\)

c

\({\mathrm{SO}}_{2}\mathrm{gas}\)

d

Hydrogen gas

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Q92
PYQ

Consider a \(70 \%\) efficient hydrogen-oxygen fuel cell working under standard conditions at 1 bar and \(298 \mathrm{~K}\). Its cell reaction is \(\mathrm{H}_{2}(\mathrm{~g})+\frac{1}{2} \mathrm{O}_{2}(\mathrm{~g}) \rightarrow \mathrm{H}_{2} \mathrm{O}(\mathrm{l})\)

The work derived from the cell on the consumption of \(1.0 \times 10^{-3} \mathrm{~mol}^{2}\) of \(\mathrm{H}_{2}(\mathrm{~g})\) is used to compress \(1.00 \mathrm{~mol}\) of a monoatomic ideal gas in a thermally insulated container. What is the change in the temperature (in K) of the ideal gas? The standard reduction potentials for the two half-cells are given below:

\(\mathrm{O}_{2}(\mathrm{~g})+4 \mathrm{H}^{+}(\mathrm{aq})+4 \mathrm{e}^{-} \rightarrow 2 \mathrm{H}_{2} \mathrm{O}(\mathrm{l}), \mathrm{E}^{\circ}=1.23 \mathrm{~V}\),

\(2 \mathrm{H}^{+}(\mathrm{aq})+2 \mathrm{e}^{-} \rightarrow \mathrm{H}_{2}(\mathrm{~g}), \mathrm{E}^{\circ}=0.00 \mathrm{~V}\).

Use \(\mathrm{F}=96500 \mathrm{~C} \mathrm{mol}^{-1}, \mathrm{R}=8.314 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}\). (Nearest integer)

[JEE Advanced 2020, Paper-1]

a

13

b

12

c

11

d

14

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Q93
PYQ

At \(25^\circ \mathrm{C}\), the molar conductance at infinite dilution for the strong electrolytes \(\mathrm{NaOH},\mathrm{NaCl}\mathrm{and}{\mathrm{BaCl}}_{2}\mathrm{are}248\times {10}^{-4},126\times {10}^{-4}\mathrm{and}280\times {10}^{-4}{\mathrm{Sm}}^{2}{\mathrm{mol}}^{-1}\)respectively. \({∧}_{\mathrm{m}}^{∘}\mathrm{Ba}{\left(\mathrm{OH}\right)}_{2}\mathrm{in}{\mathrm{Sm}}^{2}{\mathrm{mol}}^{-1}\mathrm{is}\)

a

\(52.4\times {10}^{-4}\)

b

\(524\times {10}^{-4}\)

c

\(402\times {10}^{-4}\)

d

\(262\times {10}^{-4}\)

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Q94
PYQ

Consider the cell at \(25^{\circ} \mathrm{C}\)

\(\mathrm{Zn} \mid \mathrm{Zn}^{2+}(\mathrm{aq}),(1 \mathrm{~M}) \| \mathrm{Fe}^{3+}(\mathrm{aq}), \mathrm{Fe}^{2+}\) (aq) | Pt(s)

The fraction of total iron present as \(\mathrm{Fe}^{3+}\) ion at the cell potential of \(1.500 \mathrm{~V}\) is \(x \times 10^{-2}\). The value of \(x\) is ____. (Nearest integer)

(Given: \({\mathrm{E}}_{{\mathrm{Fe}}^{3+}/{\mathrm{Fe}}^{2+}}^{\mathrm{o}}=0.77\mathrm{V},{\mathrm{E}}_{{\mathrm{zn}}^{2+}/\mathrm{Zn}}^{\mathrm{o}}=−0.76\mathrm{V},\)\(\sqrt{10}=3.16\))

a

24

b

34

c

54

d

16

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Q95
PYQ

The resistivity of a \(0.8 \mathrm{~M}\) solution of an electrolyte is \(5 \times 10^{-3} \Omega \mathrm{cm}\). Its molar conductivity is ______\(\times 10^{4} \Omega^{-1}\) \(\mathrm{cm}^{2} \mathrm{~mol}^{-1}\). (Nearest integer)

a

25

b

20

c

15

d

10

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Q96
PYQ

Statement I: The limiting molar conductivity of \({KCl}\) (strong electrolyte) is higher compared to that of \({CH}_3 COOH\) (weak electrolyte).
Statement II: Molar conductivity decreases with decrease in concentration of electrolyte.

a

Statement I is true, but Statement II is false

b

Statement I is false, but Statement II is true

c

Both Statement I and Statement II are true

d

Both Statement I and Statement II are false

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Q97
PYQ

Match List-I with List-II.

List-I

(Parameter)

List-II

(Unit)

(A) Cell constant (I) \(\mathrm{S}{\mathrm{m}}^{2}{\mathrm{mol}}^{-1}\)
(B) Molar conductivity (II) Dimensionless
(C) Conductivity (III) \(\mathrm{m}^{-1}\)
(D) Degree of dissociation of electrolyte (IV) \(\Omega^{-1} \mathrm{~m}^{-1}\)

Choose the correct answer from the options given below:

a

(A)-(III); (B)-(I); (C)-(II); (D)-(IV)

b

(A)-(II); (B)-(I); (C)-(III); (D)-(IV)

c

(A)-(III); (B)-(I); (C)-(IV); (D)-(II)

d

(A)-(I); (B)-(IV); (C)-(III); (D)-(II)

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Q98
PYQ

Statement I: The limiting molar conductivity of \({KCl}\) (strong electrolyte) is higher compared to that of \(CH_3 COOH\) (weak electrolyte)
Statement II: Molar conductivity decreases with decrease in concentration of electrolyte.

In the light of the above statements, choose the most appropriate answer from the options given below.

[JEE Main 2021, 26 Aug (Shift 1)]

a

Statement I is true, but Statement II is false

b

Statement I is false, but Statement II is true

c

Both Statement I and Statement II are true

d

Both Statement I and Statement II are false

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Q99
PYQ

\( 250 \mathrm{~mL} \) of a waste solution obtained from the workshop of a goldsmith contains \( 0.1 \mathrm{~M} \mathrm{~AgNO}_{3} \) and \( 0.1 \mathrm{~M} \mathrm{~AuCl} \). The solution was electrolyzed at \( 2 \mathrm{~V} \) by passing a current of \( 1 \mathrm{~A} \) for 15 minutes. The metal/metals electrodeposited will be

\[ \left[\mathrm{E}_{\mathrm{Ag}^{*} / \mathrm{Ag}}^{0}=0.80 \mathrm{~V}, \mathrm{E}_{\mathrm{Au}^{*} / \mathrm{Au}}^{0}=1.69 \mathrm{~V}\right] \]

[JEE Main 2020, 4 Sep (Shift 2)]

a

Silver and gold in equal mass proportion

b

Silver and gold in proportion to their atomic weights

c

Only gold

d

Only silver

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Q100
PYQ

The equation that is incorrect is

[JEE Main 2020, 7 Jan (Shift 2)]

a

\(\left(\Lambda_{\mathrm{m}}^{\circ}\right)_{\mathrm{NaBr}}-\left(\Lambda_{\mathrm{m}}^{\circ}\right)_{\mathrm{NaCl}}=\left(\Lambda_{\mathrm{m}}^{\circ}\right)_{\mathrm{KBr}}-\left(\Lambda_{\mathrm{m}}^{\circ}\right)_{\mathrm{KCl}}\)

b

\(\left(\Lambda_{\mathrm{m}}^{\circ}\right)_{\mathrm{H}_{2} \mathrm{O}}=\left(\Lambda_{\mathrm{m}}^{\circ}\right)_{\mathrm{HCl}}+\left(\Lambda_{\mathrm{m}}^{\circ}\right)_{\mathrm{NaOH}}-\left(\Lambda_{\mathrm{m}}^{\circ}\right)_{\mathrm{NaCl}}\)

c

\(\left(\Lambda_{\mathrm{m}}^{\circ}\right)_{\mathrm{NaBr}}-\left(\Lambda_{\mathrm{m}}^{\circ}\right)_{\mathrm{NaI}}=\left(\Lambda_{\mathrm{m}}^{\circ}\right)_{\mathrm{KBr}}-\left(\Lambda_{\mathrm{m}}^{\circ}\right)_{\mathrm{NaBr}}\)

d

\(\left(\Lambda_{\mathrm{m}}^{\circ}\right)_{\mathrm{KCl}}-\left(\Lambda_{\mathrm{m}}^{\circ}\right)_{\mathrm{NaCl}}=\left(\Lambda_{\mathrm{m}}^{\circ}\right)_{\mathrm{KBr}}-\left(\Lambda_{\mathrm{m}}^{\circ}\right)_{\mathrm{NaBr}}\)

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Q101
PYQ

Plotting \(1 / \Lambda_{\mathrm{m}}\) against \(\mathrm{c} \Lambda_{\mathrm{m}}\) for aqueous solutions of a monobasic weak acid (HX) resulted in a straight line with \(\mathrm{y}\)-axis intercept of \(\mathrm{P}\) and slope of \(\mathrm{S}\). The ratio \(\mathrm{P} / \mathrm{S}\) is

\(\left[\Lambda_{\mathrm{m}}=\right.\) molar conductivity

\(\Lambda_{\mathrm{m}}^{\circ}=\) limiting molar conductivity

\(\mathrm{c}=\) molar concentration

\(\mathrm{K}_{\mathrm{a}}=\) dissociation constant of HX]

[JEE Advanced 2023, Paper-1]

a

\(\mathrm{K}_{\mathrm{a}} \Lambda_{\mathrm{m}}^{\circ}\)

b

\(\mathrm{K}_{\mathrm{a}} \Lambda_{\mathrm{m}}^{\circ} / 2\)

c

\(2 \mathrm{~K}_{\mathrm{a}} \Lambda_{\mathrm{m}}^{\circ}\)

d

\(1 /\left(\mathrm{K}_{\mathrm{a}} \Lambda_{\mathrm{m}}^{\circ}\right)\)

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Q102
PYQ

The product obtained from the electrolytic oxidation of acidified sulphate solutions, is :

a

\( \mathrm{HSO}_{4}^{-} \)

b

\( \mathrm{HO}_{3} \mathrm{SOOSO}_{3} \mathrm{H} \)

c

\( \mathrm{HO}_{2} \mathrm{SOSO}_{2} \mathrm{H} \)

d

\( \mathrm{HO}_{3} \mathrm{SOSO}_{3} \mathrm{H} \)

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Q103
PYQ

Electrode potential data are given below:
\(F{e}^{+3}(aq)+{e}^{-}\to F{e}^{+2}(aq);E^\circ =+0.77V\) \(A{l}^{+3}(aq)+3{e}^{-}\to Al(s);E^\circ =-1.66V\) \(B{r}_{2}(aq)+2{e}^{-}\to 2B{r}^{-}(aq);E^\circ =+1.08V\)
Based on the data, the reducing power of \(F{e}^{+2}\), Al and \(B{r}^{-}\) will increase in the order

(PYQ-2023)

a

\(B{r}^{-}

b

\(F{e}^{+2}

c

\(Al

d

\(Al

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Q104
PYQ

At \(298 \mathrm{~K}\), the standard reduction potential for \(\mathrm{Cu}^{2+} / \mathrm{Cu}\) electrode is \(0.34 \mathrm{~V}\).

Given: \(\mathrm{K}_{\mathrm{sp}} \mathrm{Cu}(\mathrm{OH})_{2}=1 \times 10^{-20}\)

Take \(\frac{2.303 \mathrm{RT}}{\mathrm{F}}=0.059 \mathrm{~V}\)

The reduction potential at \(\mathrm{pH}=14\) for the above couple is \((-) \mathrm{x} \times 10^{-2} \mathrm{~V}\). The value of \(\mathrm{x}\) is _____.

[JEE Main 2023, 13 Apr (Shift 2)]

a

25

b

30

c

46

d

56

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Q105
PYQ

Plotting 1/Λm against cΛm for aqueous solution of a monobasic weak acid (HX) resulted in a straight line with y-axis intercept of P and slope of S. The ratio P⁄S is

m = molar conductivity

\({\Lambda }_{\mathrm{m}}^{^\circ }=\)limiting molar conductivity

c = molar concentration

Ka = dissociation constant of HX]

a

\({\mathrm{K}}_{\mathrm{a}}{\Lambda }_{\mathrm{m}}^{^\circ }\)

b

\({\mathrm{K}}_{\mathrm{a}}{\Lambda }_{\mathrm{m}}^{^\circ }/2\)

c

\(2{\mathrm{K}}_{\mathrm{a}}{\Lambda }_{\mathrm{m}}^{^\circ }\)

d

\(1/\left({\mathrm{K}}_{\mathrm{a}}{\Lambda }_{\mathrm{m}}^{^\circ }\right)\)

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Q106
PYQ

For the disproportionation reaction \(2 \mathrm{Cu}^{+}(\mathrm{aq}) \rightleftharpoons \mathrm{Cu}(\mathrm{s})+\mathrm{Cu}^{2+}(\mathrm{aq})\) at \(298 \mathrm{~K}\), In \(\mathrm{K}\) (where \(\mathrm{K}\) is the equilibrium constant) is _____\(\times 10^{-1}\).

Given :

\(\left({\mathrm{E}}_{{\mathrm{Cu}}^{2+}/{\mathrm{Cu}}^{+}}^{\mathrm{o}}=0.16\mathrm{V},{\mathrm{E}}_{{\mathrm{Cu}}^{2+}/\mathrm{Cu}}^{\mathrm{o}}=0.52\mathrm{V},\frac{\mathrm{RT}}{\mathrm{F}}=0.025\right)\)

[JEE Main 2020, 2 Sep (Shift 2)]

a

288

b

123

c

145

d

200

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Q107
PYQ

Given below are two statements

Statement-I: The limiting molar conductivity of \( \mathrm{KCl} \) (strong electrolyte) is higher as compared to that of \( \mathrm{CH}_{3} \mathrm{COOH} \) (weak electrolyte).

Statement-II: Molar conductivity decreases with decrease in concentration of electrolyte.

In the light of the above statements, choose the most appropriate answer from the options given below:

a

Statement-I is true but Statement-II is false

b

Both Statement-I and Statement-II are false

c

Both Statement-I and Statement-II are true

d

Statement-I is false but Statement-II is true

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Q108
PYQ

An acidic solution of dichromate is electrolyzed for 8 minutes using \(2 \mathrm{~A}\) current. As per the following equation

\( \mathrm{Cr}_2 \mathrm{O}_7^{2-}+14 \mathrm{H}^{+}+6 \mathrm{e}^{-} \rightarrow 2 \mathrm{Cr}^{3+}+7 \mathrm{H}_2 \mathrm{O}\)
The amount of \(\mathrm{Cr}^{3+}\) obtained was 0.104 g. The efficiency of the process(in %) is ______. (Take : \(F=96000 \mathrm{~C}\), At. mass of chromium \(=52\) )

[JEE Main 2020, 3 Sep (Shift 2)]

a

60

b

65

c

70

d

75

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Q109
PYQ

Given below are two statements :
\(1\) M aqueous solution of each of \(\mathrm{Cu}{\left({\mathrm{NO}}_{3}\right)}_{2}\), \({\mathrm{AgNO}}_{3},{\mathrm{Hg}}_{2}{\left({\mathrm{NO}}_{3}\right)}_{2},\mathrm{Mg}{\left({\mathrm{NO}}_{3}\right)}_{2}\) are electrolysed using inert electrodes
Given : \({\mathrm{E}}_{{\mathrm{Ag}}^{+}/\mathrm{Ag}}^{\theta }=0.80\mathrm{V},{\mathrm{E}}_{{\mathrm{Hg}}_{2}^{2+}/\mathrm{Hg}}^{\theta }=0.79\mathrm{V}\), \({\mathrm{E}}_{{\mathrm{Cu}}^{2+}/\mathrm{Cu}}^{\theta }=0.24\mathrm{V}\text{ and }{\mathrm{E}}_{{\mathrm{Mg}}^{2+}/\mathrm{Mg}}^{\theta }=-2.37\mathrm{V}\)
Statement (I) : With increasing voltage, the sequence of deposition of metals on the cathode will be Ag, Hg and Cu
Statement (II) : Magnesium will not be deposited at cathode instead oxygen gas will be evolved at the cathode.
In the light of the above statement, choose the most appropriate answer from the options given below

a

Both statement I and statement II are incorrect

b

Statement I is correct but statement II is incorrect

c

Both statement I and statement II are correct

d

Statement I is incorrect but statement II is correct

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Q110
PYQ

The electrode potential of the following half cell at \(298 \mathrm{~K}\).

\(\mathrm{X}\left|\mathrm{X}^{2+}(0.001 \mathrm{M}) \| \mathrm{Y}^{2+}(0.01 \mathrm{M})\right| \mathrm{Y}\) is _______\(\times 10^{-2} \mathrm{~V}\) (Nearest integer).

Given: \(\begin{aligned} \mathrm{E}_{\mathrm{x}^{2+}{ }_{\mathrm{X}}}^0 & =-2.36 \mathrm{~V} \\ \mathrm{E}_{\mathrm{Y}^{2+} \mid \mathrm{Y}}^0 & =+0.36 \mathrm{~V}\end{aligned}\)

\(\frac{2.303 \mathrm{RT}}{\mathrm{F}}=0.06 \mathrm{~V}\)

[JEE Main 2023, 30 Jan (Shift 2)]

a

275

b

2.72

c

267

d

225

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Q111
PYQ

For lead storage battery pick the correct statements

(A) During charging of battery, \(\mathrm{PbSO}_{4}\) on anode is converted into \(\mathrm{PbO}_{2}\)

(B) During charging of battery, \(\mathrm{PbSO}_{4}\) on cathode is converted into \(\mathrm{PbO}_{2}\)

(C) Lead storage battery, consists of grid of lead packed with \(\mathrm{PbO}_{2}\) as anode

(D) Lead storage battery has \(\sim 38 \%\) solution of sulphuric acid as an electrolyte

Choose the correct answer from the options given below

[JEE Main 2023, 12 Apr (Shift 1)]

a

(B), (D) only

b

(B), (C), (D) only

c

(A), (B), (D) only

d

(B), (C) only

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Q112
PYQ

The resistance of a conductivity cell with cell constant \( 1.14 \mathrm{~cm}^{-1} \), containing \( 0.001 \mathrm{~M} \mathrm{~KCl} \) at \( 298 \mathrm{~K} \) is \( 1500 ~\Omega \). The molar conductivity of \( 0.001 \mathrm{~M} \mathrm{~KCl} \) solution at \( 298 \mathrm{~K}{\text { }} in \mathrm{~S} \mathrm{~cm}^{2} \mathrm{~mol}^{-1} \) is......

(Integer answer)

[JEE Main 2021, 27 Aug (Shift 2)]

a

760

b

740

c

720

d

700

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Q113
PYQ

The specific conductance of \(0.0025 \mathrm{M}\) acetic acid is \(5 \times 10^{-5} \mathrm{~S} \mathrm{~cm}^{-1}\) at a certain temperature. The dissociation constant of acetic acid is ___ \(\times 10^{-7}\). (Nearest integer). Consider limiting molar conductivity of \(\mathrm{CH}_{3} \mathrm{COOH}\) as \(400 \mathrm{~S} \mathrm{~cm}^{2} \mathrm{~mol}^{-1}\)

a

66

b

56

c

46

d

36

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Q114
PYQ

The standard electrode potential of \(\mathrm{M}^{+} / \mathrm{M}\) in aqueous solution does not depend on

[JEE Main 2023, 6 Apr (Shift 1)]

a

Ionisation of a gaseous metal atom

b

Ionisation of a solid metal atom

c

Hydration of a gaseous metal ion

d

Sublimation of a solid metal

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Q115
PYQ

Find electrode potential at pH = 5 for

2H₂O → O₂ + 4H⁺ + 4e⁻
E° = -1.23 V

[JEE Main 2020, 8 Jan (Shift 1)]

a

-0.93

b

-0.83

c

+0.69

d

+0.96

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Q116
PYQ

At what \(\mathrm{pH}\), given half cell \(\mathrm{MnO}_{4}^{-}(0.1 \mathrm{~M}) \mid \mathrm{Mn}^{2+}(0.001 \mathrm{~M})\) will have electrode potential of \(1.282 \mathrm{~V}\) ?

(Nearest Integer)

Given: \(\mathrm{E}_{\mathrm{MnO}_{4}^{-} / \mathrm{Mn}^{2+}}^{\circ}=1.54 \mathrm{~V}, \frac{2.303 \mathrm{RT}}{\mathrm{F}}=0.059 \mathrm{~V}\)

[JEE Main 2023, 1 Feb (Shift 1)]

a

2

b

3

c

4

d

5

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Q117
PYQ

An oxidation-reduction reaction in which 3 electrons are transferred has \(\Delta \mathrm{G}^{\circ}\) of \(17.37 \mathrm{~kJ} \mathrm{~mol}^{-1}\) at \(25^{\circ} \mathrm{C}\). The value of \(\mathrm{E}_{\text {cell }}^{0}\) (in \(\mathrm{V}\) ) is -------------\(\times 10^{-2}\). \(\left(1 \mathrm{~F}=96,500 \mathrm{~C} \mathrm{mol}^{-1}\right)\)

[JEE Main 2020, 5 Sep (Shift 1)]

a

-6

b

-5

c

6

d

5

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