JEEChemistry

Equilibrium

112 JEE Chemistry previous year questions on Equilibrium — options free on every question; 11 include the answer & explanation free, the rest unlock with PYQ Pass.

Q1 FREE PREVIEW
PYQ
pH of water is 7 at 25 degree celsius. If water is heated to 80 degree celsius, it's pH will:
aIncrease
bHydrogen ion concentration increases, hydroxyl ion concentration decreases
cDecrease
dRemains the same
✓ Correct answer: c) Decrease
ExplanationAs water is heated to 80°C, the auto-ionization of water ( ) increases, leading to a higher H⁺ concentration.Since pH = -log[H⁺], an increase in H⁺ results in a lower pH, though water remains neutral as [H⁺] = [OH⁻].
Q2 FREE PREVIEW
PYQ
pH of water is 7 at 25 degree celsius. If water is heated to 80 degree celsius, it's pH will be : [JEE Main 2025, 23 Jan (Shift 2)]
aIncrease
bHydrogen ion concentration increases, hydroxyl ion concentration decreases
cDecrease
dRemains the same
✓ Correct answer: c) Decrease
ExplanationAs water is heated to 80°C, the auto-ionization of water ( ) increases, leading to a higher H⁺ concentration.Since pH = -log[H⁺], an increase in H⁺ results in a lower pH, though water remains neutral as [H⁺] = [OH⁻].
Q3 FREE PREVIEW
PYQ

A vessel at 1000 K contains carbon dioxide with a pressure of 0.5 atm. Some of carbon dioxide is converted into carbon monoxide on addition of graphite. If total pressure at equilibrium is 0.8 atm, then \({\mathrm{K}}_{\mathrm{p}}\) is

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

a

3 atm

b

1.8 atm

c

0.18 atm

d

0.3 atm

✓ Correct answer: b)

1.8 atm

Explanation

\({\mathrm{CO}}_{2}\left(\mathrm{g}\right)+\mathrm{C}\left(\mathrm{s}\right)⇌2\mathrm{CO}\left(\mathrm{g}\right)\\ 0.5-\\ 0.5-\mathrm{x}2\mathrm{x}\\ {\mathrm{P}}_{\mathrm{T}}=0.5+\mathrm{x}=0.8\\ \mathrm{x}=0.8-0.5=0.3\\ {\mathrm{K}}_{\mathrm{P}}=\frac{{(0.6)}^{2}}{0.2}=1.8\)

Q4 FREE PREVIEW
PYQ

If equal volumes of \({\mathrm{AB}}_{2}\) and XY (both are salts) aqueous solutions are mixed, which of the following combination will give a precipitate of \({\mathrm{AY}}_{2}\) at \(300\) K ?
\((\mathrm{Given}{\mathrm{K}}_{\mathrm{sp}}(\mathrm{at}300\mathrm{K})\)\(\mathrm{for}{\mathrm{AY}}_{2}=5.2\times {10}^{-7})\)

[JEE Main 2025, 2 Apr (Shift 1)]

a

\(3.6\times {10}^{-3}\mathrm{M}{\mathrm{AB}}_{2},5.0\times {10}^{-4}\mathrm{M}\mathrm{XY}\)

b

\(2.0\times {10}^{-4}\mathrm{M}{\mathrm{AB}}_{2},0.8\times {10}^{-3}\mathrm{M}\mathrm{XY}\)

c

\(2.0\times {10}^{-2}\mathrm{M}{\mathrm{AB}}_{2},2.0\times {10}^{-2}\mathrm{M}\mathrm{XY}\)

d

\(1.5\times {10}^{-4}\mathrm{M}{\mathrm{AB}}_{2},1.5\times {10}^{-3}\mathrm{M}\mathrm{XY}\)

✓ Correct answer: c)

\(2.0\times {10}^{-2}\mathrm{M}{\mathrm{AB}}_{2},2.0\times {10}^{-2}\mathrm{M}\mathrm{XY}\)

Explanation

For precipitation of AY₂:
Ksp = [A²⁺][Y⁻]² = 5.2 × 10⁻⁷

Check option C:
[A²⁺] = 2.0 × 10⁻²
[Y⁻] = 2.0 × 10⁻²

Ion product = 8.0 × 10⁻⁶ > Ksp
⇒ Precipitation occurs

Q5 FREE PREVIEW
PYQ

A weak acid HA has degree of dissociation x. Which option gives the correct expression of (\(\mathrm{pH}-{\mathrm{pk}}_{\mathrm{b}}\))

(Memory-based Question 28/ Jan/25 morning shift )

a

0

b

\((\log \left(1+2x)\right)\)

c

\(\log \left(\frac{x}{1-x}\right)\)

d

\(\log \left(\frac{1-x}{x}\right)\)

✓ Correct answer: c)

\(\log \left(\frac{x}{1-x}\right)\)

Explanation

\(\mathrm{HA}(\mathrm{aq})⇌{\mathrm{H}}^{+}(\mathrm{aq})+{\mathrm{A}}^{-}(\mathrm{aq})\\ \mathrm{C}--\\ \mathrm{C}-\mathrm{Cx}\mathrm{Cx}\mathrm{Cx}\\ {\mathrm{K}}_{\mathrm{a}}=\frac{\left[{\mathrm{H}}^{+}\right]\left[{\mathrm{A}}^{-}\right]}{\mathrm{HA}}=\frac{\mathrm{Cα}\times \mathrm{Cα}}{\mathrm{C}(1-\mathrm{x})}\\ \left[{\mathrm{H}}^{+}\right]=\mathrm{Cα}=\frac{{\mathrm{K}}_{\mathrm{a}}(1-\mathrm{x})}{\mathrm{x}}\\ \mathrm{pH}=-\log \left[{\mathrm{H}}^{+}\right]=-\log \frac{\left[{\mathrm{K}}_{\mathrm{a}}(1-\mathrm{x})\right]}{\mathrm{x}}\\ \mathrm{pH}={\mathrm{PK}}_{\mathrm{a}}-\log \frac{(1-\mathrm{x})}{\mathrm{x}}\\ \mathrm{pH}-{\mathrm{PK}}_{\mathrm{a}}=\log \frac{\mathrm{x}}{1-\mathrm{x}}\)

Q6 FREE PREVIEW
PYQ

An aqueous solution of HCl with pH 1.0 is diluted by adding equal volume of water (ignoring dissociation of water). The pH of HCl solution would
(Given log 2 = 0.30)

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

a

reduce to 0.5

b

increase to 1.3

c

remain same

d

increase to 2

✓ Correct answer: b)

increase to 1.3

Explanation

Initial pH = 1

[H⁺] = 10⁻¹ M

After adding equal volume of water → concentration becomes half

New [H⁺] = (10⁻¹) / 2

pH = −log(10⁻¹ / 2)

pH = −[log(10⁻¹) − log(2)]

pH = −[−1 − 0.30]

pH = 1 + 0.30

pH = 1.30

Q7 FREE PREVIEW
PYQ

The pH of a \(0.01\) M weak acid \(\mathrm{HX}\left({\mathrm{K}}_{\mathrm{a}}=4\times {10}^{-10}\right)\) is found to be 5 . Now the acid solution is diluted with excess of water so that the pH of the solution changes to \(6\) . The new concentration of the diluted weak acid is given as \(x\times {10}^{-4}\mathrm{M}\). The value of x is ______ (nearest integer)

a

20

b

25

c

30

d

35

✓ Correct answer: b)

25

Explanation

\(pH=6\ [{H}^{+}]={10}^{−6}\)

\([{H}^{+}]={10}^{−6}=\sqrt{{K}_{a}C}\)

\({10}^{−6}=\sqrt{4\times {10}^{−10}\times C}\)

\(\frac{{10}^{−12}}{4\times {10}^{−10}}=C\)

\(0.25\times {10}^{−2}=C\)

\(25\times {10}^{−4}=C\ ∴x=25\)

Q8 FREE PREVIEW
PYQ

What will be the effect on pH of water when it is heated

a

Increases

b

Decrease

c

Remains same

d

pH increses and then decreses

✓ Correct answer: b)

Decrease

Explanation

As water is heated degree of ionisation increases
[H+] ion concentration increases pH decreases.

Q9 FREE PREVIEW
PYQ

\({\mathrm{CO}}_{2}(\mathrm{g})+\mathrm{C}(\mathrm{s})⇌2\mathrm{CO}(\mathrm{g})\)

If initial pressure of \({\mathrm{CO}}_{2}\)is 0.6 atm and after equilibrium is established, total pressure is 0/8 atm. Then, find \({\mathrm{K}}_{\mathrm{p}}\).

(Memory Based JEE Mains 22/01/2025, Shift -1)

a

0.4

b

0.2

c

0.6

d

0.8

✓ Correct answer: a)

0.4

Explanation

\({\mathrm{CO}}_{2}(\mathrm{g})+\mathrm{C}(\mathrm{s})⇌2\mathrm{CO}(\mathrm{g})\\ \mathrm{At}\mathrm{t}=0{\mathrm{p}}_{0}--\\ \mathrm{At}\mathrm{t}=\mathrm{teq}{\mathrm{p}}_{0}-\mathrm{p}2\mathrm{p}\\ {\mathrm{P}}_{\mathrm{T}}={\mathrm{P}}_{0}+\mathrm{P}\Rightarrow \mathrm{p}=(0.8-0.6)=0.2,{\mathrm{p}}_{\mathrm{CO}}=0.4\mathrm{and}{\mathrm{p}}_{{\mathrm{CO}}_{2}}=0.4\\ {\mathrm{K}}_{\mathrm{p}}=\frac{{\mathrm{p}}_{{(\mathrm{CO})}^{2}}}{{\mathrm{p}}_{{\mathrm{CO}}_{2}}}=\frac{{(0.4)}^{2}}{0.4}=0.4\).

Q10 FREE PREVIEW
PYQ

A weak acid HA has degree of dissociation x. Which option gives the correct expression of (\(\mathrm{pH}-{\mathrm{pk}}_{\mathrm{b}}\))

(Memory-based Question 28/ Jan/25 morning shift )

a

0

b

\((\log \left(1+2x)\right)\)

c

\(\log \left(\frac{x}{1-x}\right)\)

d

\(\log \left(\frac{1-x}{x}\right)\)

✓ Correct answer: c)

\(\log \left(\frac{x}{1-x}\right)\)

Explanation

\(\mathrm{HA}(\mathrm{aq})⇌{\mathrm{H}}^{+}(\mathrm{aq})+{\mathrm{A}}^{-}(\mathrm{aq})\\ \mathrm{C}--\\ \mathrm{C}-\mathrm{Cx}\mathrm{Cx}\mathrm{Cx}\\ {\mathrm{K}}_{\mathrm{a}}=\frac{\left[{\mathrm{H}}^{+}\right]\left[{\mathrm{A}}^{-}\right]}{\mathrm{HA}}=\frac{\mathrm{Cα}\times \mathrm{Cα}}{\mathrm{C}(1-\mathrm{x})}\\ \left[{\mathrm{H}}^{+}\right]=\mathrm{Cα}=\frac{{\mathrm{K}}_{\mathrm{a}}(1-\mathrm{x})}{\mathrm{x}}\\ \mathrm{pH}=-\log \left[{\mathrm{H}}^{+}\right]=-\log \frac{\left[{\mathrm{K}}_{\mathrm{a}}(1-\mathrm{x})\right]}{\mathrm{x}}\\ \mathrm{pH}={\mathrm{PK}}_{\mathrm{a}}-\log \frac{(1-\mathrm{x})}{\mathrm{x}}\\ \mathrm{pH}-{\mathrm{PK}}_{\mathrm{a}}=\log \frac{\mathrm{x}}{1-\mathrm{x}}\)

Q11 FREE PREVIEW
PYQ

For a reaction, \({N}_{2}{O}_{5(g)}\to 2N{O}_{2(g)}+\frac{1}{2}{O}_{2(g)}\) in a constant volume container, no products were present initially. The final pressure of the system when 50 % of reaction gets completed is

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

a

7/2 times of initial pressure

b

5 times of initial pressure

c

5/2 times of initial pressure

d

7/4 times of initial pressure

✓ Correct answer: d)

7/4 times of initial pressure

Explanation

\({N}_{2}{O}_{5}(g)\to 2N{O}_{2}(g)+\frac{1}{2}{O}_{2}(g)\)

Let the initial pressure of \({N}_{2}{O}_{5}\) be \({P}_{0}\).
Initial moles: Only \({N}_{2}{O}_{5}\) is present \(\to {n}_{0}\) \(={P}_{0}\) (as per ideal gas law).
Let x be the fraction of reaction completed.
For 1 mole of \({N}_{2}{O}_{5}\) decomposing:
2 moles of \(N{O}_{2}\) are formed.
0.5 moles of \({O}_{2}\) are formed.

Given that 50 % of the reaction is completed (x =0.5):
\({N}_{2}{O}_{5}\) decomposed: \(0.5{P}_{0}\)
\(N{O}_{2}\) formed: \(2\times 0.5{P}_{0}={P}_{0}\)
\({O}_{2}\) formed: \(0.5\times 0.5{P}_{0}=0.25{P}_{0}\)
Remaining \({N}_{2}{O}_{5}:{P}_{0}-0.5{P}_{0}=0.5{P}_{0}\)
\({P}_{\text{final }}={P}_{{N}_{2}{O}_{5}}+{P}_{N{O}_{2}}+{P}_{{O}_{2}}\)
\({P}_{\text{final }}=0.5{P}_{0}+{P}_{0}+0.25{P}_{0}\)\(=1.75{P}_{0}=\frac{7}{4}{P}_{0}\)

Q12
PYQ

The solubility of barium iodate in an aqueous solution prepared by mixing 200 mL of 0.010 M barium nitrate with 100 mL of 0.10 M sodium iodate is \(X \times 10^{-6} mol dm ^{-3}\). The value of \(X\) is________ .

Use: Solubility product constant ( \(K_{ sp }\) ) of barium iodate \(=1.58 \times 10^{-9}\)

[JEE Advanced 2025, Paper-2]

a

2

b

4

c

6

d

8

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Q13
PYQ

A vessel at 1000 K contains carbon dioxide with a pressure of 0.5 atm. Some of carbon dioxide is converted into carbon monoxide on addition of graphite. If total pressure at equilibrium is 0.8 atm, then \({\mathrm{K}}_{\mathrm{p}}\)is

a

3 atm

b

1.8 atm

c

0.18 atm

d

0.3 atm

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Q14
PYQ

A weak acid HA has degree of dissociation x. Which option gives the correct expression of ( \(pH-\) \(\left.p{K}_{a}\right)\) ?

a

\(\log (1+2x)\)

b

0

c

\(\log \left(\frac{x}{1-x}\right)\)

d

\(\log \left(\frac{1-x}{x}\right)\)

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Q15
PYQ

Le-Chatelier’s principle is not applicable to

a

\({H}_{2}(g)+{I}_{2}(g)⇌2HI(g)\)

b

\(Fe(s)+S(s)⇌FeS(s)\)

c

\({N}_{2}(g)+3{H}_{2}(g)⇌2N{H}_{3}(g)\)

d

\({N}_{2}(g)+{O}_{2}(g)⇌2NO(g)\)

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Q16
PYQ

The molar solubility(s) of zirconium phosphate with molecular formula \({\left(\mathrm{Zr}\right)}_{3}{\left(P{O}_{4}\right)}_{4}\) is given by relation

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

a

\({\left(\frac{{\mathrm{K}}_{\mathrm{sp}}}{5348}\right)}^{\frac{1}{6}}\)

b

\({\left(\frac{{\mathrm{K}}_{\mathrm{sp}}}{9612}\right)}^{\frac{1}{3}}\)

c

\({\left(\frac{{\mathrm{K}}_{\mathrm{sp}}}{6912}\right)}^{\frac{1}{7}}\)

d

\({\left(\frac{{\mathrm{K}}_{\mathrm{sp}}}{8435}\right)}^{\frac{1}{7}}\)

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Q17
PYQ

Given below are two statements :
Statement 1: On passing \({\mathrm{HCl}}_{(\mathrm{g})}\) through a saturated solution of \({\mathrm{BaCl}}_{2}\), at room temperature white turbidity appears

Statement II : When \(\mathrm{HCl}\) gas is passed through a saturated solution of \(\mathrm{NaCl}\), sodium chloride is precipitated due to common ion effect.

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

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

a

Both Statement I and Statement II are incorrect

b

Both Statement I and Statement II are correct

c

Statement I is incorrect but Statement II is correct

d

Statement I is correct but Statement II is incorrect

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Q18
PYQ

Given below are two statements :
Statement 1: On passing \({\mathrm{HCl}}_{(\mathrm{g})}\) through a saturated solution of \({\mathrm{BaCl}}_{2}\), at room temperature white turbidity appears

Statement II : When \(\mathrm{HCl}\) gas is passed through a saturated solution of \(\mathrm{NaCl}\), sodium chloride is precipitated due to common ion effect.

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

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

a

Both Statement I and Statement II are incorrect

b

Both Statement I and Statement II are correct

c

Statement I is incorrect but Statement II is correct

d

Statement I is correct but Statement II is incorrect

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Q19
PYQ

Consider the equilibrium

\(CO(g)+3{H}_{2}(g)⇌C{H}_{4}(g)+{H}_{2}O(g)\)

If the pressure applied over the system increases by two fold at constant temperature then
(A) Concentration of reactants and products increases.
(B) Equilibrium will shift in forward direction.
(C) Equilibrium constant increases since concentration of products increases.
(D) Equilibrium constant remains unchanged as concentration of reactants and products remain same.
Choose the correct answer from the options given below.

[JEE Main 2023, 24 Jan (Shift 1)]

a

(A) and (B) only

b

(B) and (C) only

c

(A), (B) and (C) only

d

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

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Q20
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Ice and water are placed in a closed container at a pressure at 1 atm and temperature 273.15 K .
If the pressure of the container increases 2 times and the temperature is kept constant, than identify the correct observation from the following.

a

The amount of ice decreases

b

Volume of system increases

c

Liquid phase disappear completely

d

Solid phase (ice) disappear completely

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Q21
PYQ

\(x\mathrm{mg}\) of \(\mathrm{Mg}(\mathrm{OH}{)}_{2}\) (molar mass = 58) is required to be dissolved in 1.0 L of water to produce a pH of 10.0 at 298 K . The value of x is ______ mg. (Nearest integer)
(Given : \(\mathrm{Mg}(\mathrm{OH}{)}_{2}\) is assumed to dissociate completely in \({\mathrm{H}}_{2}\mathrm{O}\) )

a

1

b

2

c

3

d

4

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Q22
PYQ

In the following system, \({\mathrm{PCl}}_{5}(\mathrm{g})⇌{\mathrm{PCl}}_{3}(\mathrm{g})+{\mathrm{Cl}}_{2}(\mathrm{g})\) at equilibrium, upon addition of xenon gas at constant T & P, the concentration of

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

a

\({\mathrm{PCl}}_{5}\) will increase

b

\({\mathrm{Cl}}_{2}\) will decrease

c

\({\mathrm{PCl}}_{5},{\mathrm{PCl}}_{3}\&{\mathrm{Cl}}_{2}\) remain constant

d

\({\mathrm{PCl}}_{3}\) will increase

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Q23
PYQ

What will be the effect on pH of water when it is heated

a

Increases

b

Decrease

c

Remains same

d

pH increses and then decreses

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Q24
PYQ

In the following system, \({\mathrm{PCl}}_{5}(\mathrm{g})⇌{\mathrm{PCl}}_{3}(\mathrm{g})+{\mathrm{Cl}}_{2}(\mathrm{g})\) at equilibrium, upon addition of xenon gas at constant T & P, the concentration of

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

a

\({\mathrm{PCl}}_{5}\) will increase

b

\({\mathrm{Cl}}_{2}\) will decrease

c

\({\mathrm{PCl}}_{5},{\mathrm{PCl}}_{3}\&{\mathrm{Cl}}_{2}\) remain constant

d

\({\mathrm{PCl}}_{3}\) will increase

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Q25
PYQ

For a sparingly soluble salt \(A{B}_{2}\), the equilibrium concentrations of \({A}^{2+}\) ions and \({B}^{-}\)ions are \(1.2\times {10}^{-4}M\) and \(0.24\times {10}^{-3}M\), respectively. The solubility product of \(A{B}_{2}\) is :

[JEE Main 2024, 9 Apr (Shift 2)]

a

\(0.276\times {10}^{-12}\)

b

\(27.65\times {10}^{-12}\)

c

\(0.069\times {10}^{-12}\)

d

\(6.91\times {10}^{-12}\)

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Q26
PYQ

pH of water is 7 at 25 degree celsius. If water is heated to 80 degree celsius, it's pH will:

a

Increase

b

Hydrogen ion concentration increases, hydroxyl ion concentration decreases

c

Decrease

d

Remains the same

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Q27
PYQ

A weak acid HA has degree of dissociation x. Which option gives the correct expression of (\(\mathrm{pH}-{\mathrm{pk}}_{\mathrm{b}}\))

(Memory-based Question 28/ Jan/25 morning shift )

a

0

b

\((\log \left(1+2x)\right)\)

c

\(\log \left(\frac{x}{1-x}\right)\)

d

\(\log \left(\frac{1-x}{x}\right)\)

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Q28
PYQ

If equal volumes of \({\mathrm{AB}}_{2}\) and XY (both are salts) aqueous solutions are mixed, which of the following combination will give a precipitate of \({\mathrm{AY}}_{2}\) at \(300\) K ?
\((\mathrm{Given}{\mathrm{K}}_{\mathrm{sp}}(\mathrm{at}300\mathrm{K})\)\(\mathrm{for}{\mathrm{AY}}_{2}=5.2\times {10}^{-7})\)

a

\(3.6\times {10}^{-3}\mathrm{M}{\mathrm{AB}}_{2},5.0\times {10}^{-4}\mathrm{M}\mathrm{XY}\)

b

\(2.0\times {10}^{-4}\mathrm{M}{\mathrm{AB}}_{2},0.8\times {10}^{-3}\mathrm{M}\mathrm{XY}\)

c

\(2.0\times {10}^{-2}\mathrm{M}{\mathrm{AB}}_{2},2.0\times {10}^{-2}\mathrm{M}\mathrm{XY}\)

d

\(1.5\times {10}^{-4}\mathrm{M}{\mathrm{AB}}_{2},1.5\times {10}^{-3}\mathrm{M}\mathrm{XY}\)

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Q29
PYQ

\({K}_{sp}\) for \(Cr(OH{)}_{3}\) is \(1.6\times {10}^{-30}\). What is the molar solubility of this salt in water?

a

\(\frac{1.8\times {10}^{-30}}{27}\)

b

\(\sqrt[4]{\frac{1.6\times {10}^{-30}}{27}}\)

c

\(\sqrt[2]{1.6\times {10}^{-30}}\)

d

\(\sqrt[5]{1.8\times {10}^{-30}}\)

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Q30
PYQ

\({K}_{sp}\) for \(Cr(OH{)}_{3}\) is \(1.6\times {10}^{-30}\). What is the molar solubility of this salt in water?

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

a

\(\frac{1.8\times {10}^{-30}}{27}\)

b

\(\sqrt[4]{\frac{1.6\times {10}^{-30}}{27}}\)

c

\(\sqrt[2]{1.6\times {10}^{-30}}\)

d

\(\sqrt[5]{1.8\times {10}^{-30}}\)

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Q31
PYQ

At temperature T, compound \(A{B}_{2(g)}\) dissociates as \(A{B}_{2(g)}⇌AB(g)+\frac{1}{2}{B}_{2(g)}\) having degree of dissociation x (small compared to unity). The correct expression for x in terms of \({K}_{p}\) and p is

a

\(\sqrt[3]{\frac{2{K}_{p}^{2}}{p}}\)

b

\(\sqrt{{K}_{p}}\)

c

\(\sqrt[3]{\frac{2{K}_{p}}{p}}\)

d

\(\sqrt[4]{\frac{2{K}_{p}}{p}}\)

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Q32
PYQ

A weak acid HA has degree of dissociation x. Which option gives the correct expression of ( \(pH-\) \(\left.p{K}_{a}\right)\)?

a

\(\log (1+2x)\)

b

0

c

\(\log \left(\frac{x}{1-x}\right)\)

d

\(\log \left(\frac{1-x}{x}\right)\)

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Q33
PYQ

The equilibrium constant for the reaction
\(S{O}_{3}(g)⇌S{O}_{2}(g)+\frac{1}{2}{O}_{2}(g)\)
is \({K}_{c}=4.9\times {10}^{-2}\). The value of \({K}_{c}\) for the reaction given below is \(2S{O}_{2}(g)+{O}_{2}(g)⇌2S{O}_{3}(g)\) is :

a

4.9

b

49

c

41.6

d

416

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Q34
PYQ

The pH of 1 N aqueous solutions of HCl, \(C{H}_{3}COOH\) and HCOOH follows the order:

a

\(HCl>HCOOH>C{H}_{3}COOH\)

b

\(HCl=HCOOH>C{H}_{3}COOH\)

c

\(C{H}_{3}COOH>HCOOH>HCl\)

d

\(C{H}_{3}COOH=HCOOH>HCl\)

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Q35
PYQ

At \(25^\circ \mathrm{C}\), the concentration of \({\mathrm{H}}^{+}\) ions in \(1.00\times {10}^{-3}\mathrm{M}\) aqueous solution of a weak monobasic acid having acid dissociation constant \(\left({K}_{\mathrm{a}}\right)\) of \(4.00\times {10}^{-11}\) is \(X\times {10}^{-7}\mathrm{M}\). The value of \(X\) is (nearest integer)___________
Use: Ionic product of water \(\left({K}_{\mathrm{w}}\right)=1.00\times {10}^{-14}\) at \(25^\circ \mathrm{C}\)

a

2

b

3

c

4

d

5

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Q36
PYQ

The molar solubility(s) of zirconium phosphate with molecular formula \({\left({\mathrm{Zr}}^{4+}\right)}_{3}{\left(P{{O}_{4}}^{-3}\right)}_{4}\) is given by relation

a

\({\left(\frac{{\mathrm{K}}_{\mathrm{sp}}}{5348}\right)}^{\frac{1}{6}}\)

b

\({\left(\frac{{\mathrm{K}}_{\mathrm{sp}}}{9612}\right)}^{\frac{1}{3}}\)

c

\({\left(\frac{{\mathrm{K}}_{\mathrm{sp}}}{6912}\right)}^{\frac{1}{7}}\)

d

\({\left(\frac{{\mathrm{K}}_{\mathrm{sp}}}{8435}\right)}^{\frac{1}{7}}\)

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Q37
PYQ

Le-Chatelier’s principle is not applicable to

a

\({H}_{2}(g)+{I}_{2}(g)⇌2HI(g)\)

b

\(Fe(s)+S(s)⇌FeS(s)\)

c

\({N}_{2}(g)+3{H}_{2}(g)⇌2N{H}_{3}(g)\)

d

\({N}_{2}(g)+{O}_{2}(g)⇌2NO(g)\)

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Q38
PYQ

Consider the given following reaction

\({\mathrm{X}}_{2}\mathrm{Y}(\mathrm{s})⇌{\mathrm{X}}_{2}(\mathrm{g})+1/2{\mathrm{Y}}_{2}(\mathrm{g}).\mathrm{If}\alpha\) is the degree of dissociation. Calculate \({\mathrm{K}}_{\mathrm{p}}\)in the terms of P total pressure. (Memory Based JEE Mains 23/01/2025 ,Shift -2)

a

\({\mathrm{K}}_{\mathrm{p}}=\frac{2{\mathrm{P}}^{3/2}}{{3}^{3/2}}\)

b

\({\mathrm{K}}_{\mathrm{p}}=\frac{2{\mathrm{P}}^{3/2}}{3}\)

c

\({\mathrm{K}}_{\mathrm{p}}=\sqrt{\frac{2\mathrm{P}}{3}}\)

d

\({\mathrm{K}}_{\mathrm{p}}=\frac{\sqrt{2}\mathrm{P}}{3}\)

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Q39
PYQ

Arrange the following in increasing order of solubility product : \(Ca(OH{)}_{2},AgBr,PbS,HgS\)

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

a

\(PbS

b

\(HgS

c

\(Ca(OH{)}_{2}

d

\(HgS

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Q40
PYQ

At temperature T, compound \(A{B}_{2(g)}\) dissociates as \(A{B}_{2(g)}⇌AB(g)+\frac{1}{2}{B}_{2(g)}\) having degree of dissociation x (small compared to unity). The correct expression for x in terms of \({K}_{p}\) and p is

a

\(\sqrt[3]{\frac{2{K}_{p}^{2}}{p}}\)

b

\(\sqrt{{K}_{p}}\)

c

\(\sqrt[3]{\frac{2{K}_{p}}{p}}\)

d

\(\sqrt[4]{\frac{2{K}_{p}}{p}}\)

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Q41
PYQ

Consider the following chemical equilibrium of the gas phase reaction at a constant temperature :
\(\mathrm{A}(\mathrm{g})⇌\mathrm{B}(\mathrm{g})+\mathrm{C}(\mathrm{g})\)
If p being the total pressure, \({\mathrm{K}}_{\mathrm{p}}\) is the pressure equilibrium constant and \(\alpha\) is the degree of dissociation, then which of the following is true at equilibrium ?

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

a

If \(\mathrm{p}\) value is extremely high compared to \({\mathrm{K}}_{\mathrm{p}},\alpha \approx 1\)

b

When p increases \(\alpha\) decreases

c

If \({\mathrm{k}}_{\mathrm{p}}\) value is extremely high compared to \(\mathrm{p},\alpha\) becomes much less than unity

d

When \(\mathrm{p}\) increases \(\alpha\) increases

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Q42
PYQ

Ice and water are placed in a closed container at a pressure at 1 atm and temperature 273.15 K .
If the pressure of the container increases 2 times and the temperature is kept constant, than identify the correct observation from the following.

a

The amount of ice decreases

b

Volume of system increases

c

Liquid phase disappear completely

d

Solid phase (ice) disappear completely

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Q43
PYQ

pH of water is 7 at 25 degree celsius. If water is heated to 80 degree celsius, it's pH will be :

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

a

Increase

b

Hydrogen ion concentration increases, hydroxyl ion concentration decreases

c

Decrease

d

Remains the same

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Q44
PYQ

The pH of 1 N aqueous solutions of HCl, \(C{H}_{3}COOH\) and HCOOH follows the order:

a

\(HCl>HCOOH>C{H}_{3}COOH\)

b

\(HCl=HCOOH>C{H}_{3}COOH\)

c

\(C{H}_{3}COOH>HCOOH>HCl\)

d

\(C{H}_{3}COOH=HCOOH>HCl\)

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Q45
PYQ

For a reaction, \({N}_{2}{O}_{5(g)}\to 2N{O}_{2(g)}+\frac{1}{2}{O}_{2(g)}\) in a constant volume container, no products were present initially. The final pressure of the system when 50 % of reaction gets completed is

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

a

7/2 times of initial pressure

b

5 times of initial pressure

c

5/2 times of initial pressure

d

7/4 times of initial pressure

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Q46
PYQ

Which of the following is not correct?

[JEE Main 2024, 29 Jan (Shift 1)]

(A) \(\Delta \mathrm{G}\) is positive for a spontaneous reaction

(B) \(\Delta \mathrm{G}\) is positive for a non-spontaneous reaction

(C) \(\Delta \mathrm{G}\) is zero for a reversible reaction

(D) \(\Delta \mathrm{G}\) is equal to zero for a spontaneous reaction

a

A ,D

b

A,B,C

c

A,B

d

A,C

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Q47
PYQ

Only one litre buffer solution was prepared by adding \(0.10\) mol each of \({\mathrm{NH}}_{3}\) and \({\mathrm{NH}}_{4}\mathrm{Cl}\) in deionised water. The change in pH on addition of \(0.05\) mol of \(\mathrm{HCl}\) to the above solution is ____ \(\times {10}^{-2}\), (Nearest integer) (Given : \({\mathrm{pK}}_{\mathrm{b}}\)of \({\mathrm{NH}}_{3}=4.745\) and \({\log }_{10}3=0.477\) )

a

45

b

48

c

51

d

54

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Q48
PYQ

Given below are two statements :
Statement I : When a system containing ice in equilibrium with water (liquid) is heated, heat is absorbed by the system and there is no change in the temperature of the system until whole ice gets melted.
Statement II : At melting point of ice, there is absorption of heat in order to overcome intermolecular forces of attraction within the molecules of water in ice and kinetic energy of molecules is not increased at melting point.
In the light of the above statements, choose the correct answer from the options given below:

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

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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Q49
PYQ

For the given hypothetical reactions, the equilibrium constants are as follows :
\(\begin{aligned}& X \rightleftharpoons Y ; K _1=1.0 \\& Y \rightleftharpoons Z ; K _2=2.0 \\& Z \rightleftharpoons W ; K _3=4.0\end{aligned}\)

The equilibrium constant for the reaction \(X \rightleftharpoons W\) is

a

6.0

b

12.0

c

8.0

d

7.0

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Q50
PYQ

For a sparingly soluble salt \(A{B}_{2}\), the equilibrium concentrations of \({A}^{2+}\) ions and \({B}^{-}\)ions are \(1.2\times {10}^{-4}M\) and \(0.24\times {10}^{-3}M\), respectively. The solubility product of \(A{B}_{2}\) is :

a

\(0.276\times {10}^{-12}\)

b

\(27.65\times {10}^{-12}\)

c

\(0.069\times {10}^{-12}\)

d

\(6.91\times {10}^{-12}\)

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Q51
PYQ

An aqueous solution of HCl with pH 1.0 is diluted by adding equal volume of water (ignoring dissociation of water). The pH of HCl solution would
(Given log 2 = 0.30)

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

a

reduce to 0.5

b

increase to 1.3

c

remain same

d

increase to 2

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Q52
PYQ

Consider the equilibrium

\(CO(g)+3{H}_{2}(g)⇌C{H}_{4}(g)+{H}_{2}O(g)\)

If the pressure applied over the system increases by two fold at constant temperature then
(A) Concentration of reactants and products increases.
(B) Equilibrium will shift in forward direction.
(C) Equilibrium constant increases since concentration of products increases.
(D) Equilibrium constant remains unchanged as concentration of reactants and products remain same.
Choose the correct answer from the options given below

a

(A) and (B) only

b

(B) and (C) only

c

(A), (B) and (C) only

d

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

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Q53
PYQ

Consider the following equilibrium, \(\mathrm{CO}(\mathrm{g})+2{\mathrm{H}}_{2}(\mathrm{g})⇌{\mathrm{CH}}_{3}\mathrm{OH}(\mathrm{g})\),\(0.1\)mol of \(\mathrm{CO}\)along with a catalyst is present in a \(2{\mathrm{dm}}^{3}\) flask maintained at \(500\) K . Hydrogen is introduced into the flask until the pressure is 5 bar and \(0.04\) mol of \({\mathrm{CH}}_{3}\mathrm{OH}\) is formed. The \({\mathrm{K}}_{\mathrm{p}}^{0}\) is _________ \(\times {10}^{-3}\) (nearest integer).
Given : \(\mathrm{R}=0.08{\mathrm{dm}}^{3}\mathrm{bar}{\mathrm{K}}^{-1}{\mathrm{mol}}^{-1}\) bar \({\mathrm{K}}^{-1}{\mathrm{mol}}^{-1}\)
Assume only methanol is formed as the product and the system follows ideal gas behaviour.

[JEE Main 2025, 2 Apr (Shift 1)]

a

70

b

72

c

74

d

76

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Q54
PYQ

Consider the given following reaction

\({\mathrm{X}}_{2}\mathrm{Y}(\mathrm{s})⇌{\mathrm{X}}_{2}(\mathrm{g})+1/2{\mathrm{Y}}_{2}(\mathrm{g}).\mathrm{If}\alpha\) is the degree of dissociation. Calculate \({\mathrm{K}}_{\mathrm{p}}\)in the terms of P total pressure. (Memory Based JEE Mains 23/01/2025 ,Shift -2)

a

\({\mathrm{K}}_{\mathrm{p}}=\frac{2{\mathrm{P}}^{3/2}}{{3}^{3/2}}\)

b

\({\mathrm{K}}_{\mathrm{p}}=\frac{2{\mathrm{P}}^{3/2}}{3}\)

c

\({\mathrm{K}}_{\mathrm{p}}=\sqrt{\frac{2\mathrm{P}}{3}}\)

d

\({\mathrm{K}}_{\mathrm{p}}=\frac{\sqrt{2}\mathrm{P}}{3}\)

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Q55
PYQ

Consider the following chemical equilibrium of the gas phase reaction at a constant temperature :
\(\mathrm{A}(\mathrm{g})⇌\mathrm{B}(\mathrm{g})+\mathrm{C}(\mathrm{g})\)
If p being the total pressure, \({\mathrm{K}}_{\mathrm{p}}\) is the pressure equilibrium constant and \(\alpha\) is the degree of dissociation, then which of the following is true at equilibrium ?

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

a

If \(\mathrm{p}\) value is extremely high compared to \({\mathrm{K}}_{\mathrm{p}},\alpha \approx 1\)

b

When p increases \(\alpha\) decreases

c

If \({\mathrm{k}}_{\mathrm{p}}\) value is extremely high compared to \(\mathrm{p},\alpha\) becomes much less than unity

d

When \(\mathrm{p}\) increases \(\alpha\) increases

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Q56
PYQ

Arrange the following in increasing order of solubility product : \(Ca(OH{)}_{2},AgBr,PbS,HgS\)

a

\(PbS

b

\(HgS

c

\(Ca(OH{)}_{2}

d

\(HgS

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Q57
PYQ

Find the value of solubility of zirconium phosphate with formula \(\left[{\mathrm{Zr}}_{3}{\left({\mathrm{PO}}_{4}\right)}_{4}\right]\) in terms of solubility product Ksp

(memory based jee mains shift-2 22/01/2025)

a

\(\mathrm{s}={\left(\frac{\mathrm{Ksp}}{6912}\right)}^{1/7}\)

b

\(\mathrm{s}=\mathrm{Ksp}\times {4352}^{4/3}\)

c

\(\mathrm{s}={\left(\frac{6912}{\mathrm{ksp}}\right)}^{4/5}\)

d

\(\mathrm{s}={\left(\frac{2345}{\mathrm{Ksp}}\right)}^{5/3}\)

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Q58
PYQ

Ice and water are placed in a closed container at a pressure of 1 atm and temperature 273.15 K . If pressure of the system is increased 2 times, keeping temperature constant, then identify correct observation from following

[JEE Main 2025, 28 Jan (Shift 1)]

a

Liquid phase disappears completely.

b

The amount of ice decreases.

c

The solid phase (ice) disappears completely.

d

Volume of system increases .

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Q59
PYQ

Ice and water are placed in a closed container at a pressure of 1 atm and temperature 273.15 K. If pressure of the system is increased 2 times, keeping temperature constant, then identify correct observation from following

[JEE Main 2025, 28 Jan (Shift 1)]

a

Liquid phase disappears completely.

b

The amount of ice decreases.

c

The solid phase (ice) disappears completely.

d

Volume of system increases .

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Q60
PYQ

Consider the following reaction (memory based jee mains shift-1 29/01/2025)

\({\mathrm{A}}_{2}\mathrm{B}\left(\mathrm{g}\right)⇌{\mathrm{A}}_{2}\left(\mathrm{g}\right)+\frac{1}{2}{\mathrm{B}}_{2}\left(\mathrm{g}\right)\)

If 'P' is the total pressure at equilibrium and K is the equilibrium constant, then \(\alpha\) in terms of K and P will be

a

\(\alpha ={\left(\frac{2{{\mathrm{K}}_{\mathrm{p}}}^{2}}{\mathrm{P}}\right)}^{1/3}\)

b

\(\alpha =\frac{2{\mathrm{K}}_{\mathrm{p}}}{\mathrm{P}}\)

c

\(\alpha ={\left(\frac{2{\mathrm{K}}_{\mathrm{p}}}{\mathrm{P}}\right)}^{1/3}\)

d

\(\alpha ={\left(\frac{3{\mathrm{K}}_{\mathrm{p}}}{2}\right)}^{1/2}\)

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Q61
PYQ

Which of the following compound CANNOT act as a Lewis base?

[JEE Main 2021, 17 Mar (Shift 1)]

a

\({\mathrm{CIF}}_{3}\)

b

\({\mathrm{PCl}}_{5}\)

c

\({\mathrm{NF}}_{3}\)

d

\({\mathrm{SF}}_{4}\)

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Q62
PYQ

Arrange the following solutions in the decreasing order of \(\mathrm{pOH}\)

(1) \(0.01\text{M}\mathrm{HCl}\)
(2) \(0.01\text{M}\mathrm{NaOH}\)
(3) \(0.01\text{M}{\mathrm{CH}}_{3}\mathrm{COONa}\)
(4) \(0.01\text{M}\mathrm{NaCl}\)


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

a

(2) > (4) > (3) > (1)

b

(2) > (3) > (4) > (1)

c

(1) > (3) > (4) > (2)

d

(1) > (4) > (3) > (2)

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Q63
PYQ

On decreasing the pH from 7 to 2, the solubility of a sparingly soluble salt (MX) of a weak acid (HX) increased from 10–4 mol L–1 to 10–3 mol L1. The pKa of HX is

a

3

b

4

c

5

d

2

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Q64
PYQ

For the following Assertion and Reason, the correct option is:

Assertion (A): The pH of water increase with increase in temperature.

Reason (R): The dissociation of water into \({\mathrm{H}}^{+}\)and \({\mathrm{OH}}^{-}\)is an exothermic reaction
[JEE Main 2020, 8 Jan (Shift 2)]

a

Assertion is not true, but reason is true

b

Both assertion and reason are false

c

Both assertion and reason are true but the reason is not the correct explanation for the assertion

d

Both assertion and reason are true, and the reason is the correct explanation for the assertion

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Q65
PYQ

Consider the reaction \( \mathrm{N}_{2} \mathrm{O}_{4}(\mathrm{~g}) \rightleftharpoons 2 \mathrm{NO}_{2}(\mathrm{~g}) \).

The temperature at which \( \mathrm{K}_{\mathrm{C}}=20.4 \) and \( \mathrm{K}_{\mathrm{P}}=600.0 \mathrm{~K} \). (Round off to the nearest integer) (Assume all gases are ideal and \( \mathrm{R}=0.0831 \mathrm{~L} \mathrm{bar} \mathrm{K}^{-1} \mathrm{~mol}^{-1} \))

[JEE Main 2021, 17 Mar (Shift 2)]

a

354

b

358

c

362

d

366

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Q66
PYQ

The ratio \(\frac{{K}_{p}}{{K}_{c}}\) for the reaction

\(\mathrm{CO}(\mathrm{g})+1/2{\mathrm{O}}_{2}⇌\mathrm{CO}(\mathrm{g})\mathrm{is}\)

a

\(\frac{1}{\sqrt{RT}}\)

b

\({\left(RT\right)}^{1/2}\)

c

\(RT\)

d

1

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Q67
PYQ

On decreasing the \(\mathrm{pH}\) from 7 to 2 , the solubility of a sparingly soluble salt (MX) of a weak acid (HX) increased from \({10}^{-4}\mathrm{mol}{\mathrm{L}}^{-1}\) to \({10}^{-3}\mathrm{mol}{\mathrm{L}}^{-1}\). The \({\mathrm{pK}}_{\mathrm{a}}\) of \(\mathrm{HX}\) is:

a

3

b

4

c

5

d

2

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Q68
PYQ

At 298 K, for the equilibrium:

\({\mathrm{PCl}}_{3}\left(\mathrm{g}\right)+{\mathrm{Cl}}_{2}\left(\mathrm{g}\right)⇄{\mathrm{PCl}}_{5}\left(\mathrm{g}\right)\)

Initial equilibrium concentrations are:
\(\left[{\mathrm{PCl}}_{3}\right]=0.20mol{L}^{-1}\\ \left[C{l}_{2}\right]=0.10mol{L}^{-1}\\ [{\mathrm{PCl}}_{5}]=0.40mol{L}^{-1}\\ {K}_{c}=20\)

Now, 0.20 mol L⁻¹ \({\mathrm{Cl}}_{2}\) is added. Find the new equilibrium concentration of \({\mathrm{PCl}}_{3}\)

a

0.049 mol L⁻¹

b

0.086 mol L⁻¹

c

0.114 mol L⁻¹

d

0.151 mol L⁻¹

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Q69
PYQ

The equilibrium constant \( \mathrm{K}_{c} \) at \( 298 \mathrm{~K} \) for the reaction \( \mathrm{A}+\mathrm{B} \rightleftharpoons \mathrm{C}+\mathrm{D} \) is 100. Starting with an equimolar solution with concentrations of \( \mathrm{A}, \mathrm{B}, \mathrm{C} \) and \( \mathrm{D} \) all equal to \( 1 \mathrm{M} \), the equilibrium concentration of \( \mathrm{D} \) is "c" M .The value of \(22\times c\) is _______.

[JEE Main 2021, 26 Aug (Shift 2)]

a

10

b

20

c

30

d

40

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Q70
PYQ

Assuming that \( \mathrm{Ba}(\mathrm{OH})_{2} \) is completely ionised in aqueous solution under the given conditions, the concentration of \( \mathrm{H}_{3} \mathrm{O}^{+} \)ions in \( 0.005 \mathrm{~M} \) aqueous solution of \( \mathrm{Ba}(\mathrm{OH})_{2} \) at 298 \( \mathrm{K} \) is \( \mathrm{x} \times 10^{-12} \mathrm{~mol} \mathrm{~L}^{-1} \). Find the value of \( \mathrm{x} \).

[JEE Main 2021, 25 Jul (Shift 2)]

a

1

b

2

c

3

d

4

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Q71
PYQ

(i) \(\mathrm{X}(\mathrm{g})⇌\mathrm{Y}(\mathrm{g})+\mathrm{Z}(\mathrm{g}){\mathrm{K}}_{{\mathrm{p}}_{1}}=3\)

(ii) \(\mathrm{A}(\mathrm{g})⇌2\mathrm{B}(\mathrm{g}){\mathrm{K}}_{{\mathrm{p}}_{2}}=1\)

If the degree of dissociation and initial concentration of both the reactants X(g) and A(g) are equal, then the ratio of the total pressure at equilibrium \(\left(\frac{{p}_{1}}{{p}_{2}}\right)\) is equal to x: 1. The value of x is (Nearest integer)

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

a

10

b

12

c

14

d

16

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Q72
PYQ

The \({\mathrm{OH}}^{-}\)concentration in a mixture of \(5.0\mathrm{mL}\) of \(0.0504\mathrm{M}\) \({\mathrm{NH}}_{4}\mathrm{Cl}\) and \(2\mathrm{mL}\) of \(0.0210M{\mathrm{NH}}_{3}\) solution is __________\(\mathrm{x}\times {10}^{-6}\mathrm{M}\). The value of \(\mathrm{x}\) is . (Nearest integer)

[Given \({\mathrm{K}}_{\mathrm{w}}=1\times {10}^{-14}\) and \({\mathrm{K}}_{\mathrm{b}}=1.8\times {10}^{-5}\) ]

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

a

1

b

2

c

3

d

4

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Q73
PYQ

The \({\mathrm{K}}_{\mathrm{sp}}\) for the following dissociation is \(1.6\times {10}^{-5}\)

\({\mathrm{PbCl}}_{2}(\mathrm{s})⇌{\mathrm{Pb}}^{2+}(\mathrm{aq})+2{\mathrm{Cl}}^{-}(\mathrm{aq})\)

Which of the following choices is correct for a mixture of \(300\mathrm{mL}0.134M\mathrm{Pb}{\left({\mathrm{NO}}_{3}\right)}_{2}\) and \(100\mathrm{mL}0.4M\mathrm{NaCl}\) ?

[JEE Main 2020, 9 Jan (Shift 1)]

a

Not enough data provided

b

\(\mathrm{Q}>{\mathrm{K}}_{\mathrm{sp}}\)

c

\(\mathrm{Q}<{\mathrm{K}}_{\mathrm{sp}}\)

d

\(\mathrm{Q}={\mathrm{K}}_{\mathrm{sp}}\)

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Q74
PYQ

Which of the following statement(s) is/are correct?

(A) The pH of \(1\times {10}^{-8}\) solution is 8 .

(B) The conjugate base \({\mathrm{H}}_{2}{\mathrm{PO}}_{4}^{-}\) is \(\mathrm{H}{{\mathrm{PO}}_{4}}^{2-}\).

(C) \({\mathrm{K}}_{\mathrm{W}}\) increases with increase in temperature.

(D) When a solution of weak monoprotic acid is titrated against a strong base at half neutralisation point, \(\mathrm{pH}=\frac{1}{2}{\mathrm{pK}}_{\mathrm{a}}\)

Choose the correct answer from the option given below.

[JEE Main 2023, 15 Apr (Shift 1)]

a

(B), (C), (D)

b

(A), (D)

c

(A),(B),(C)

d

(B), (C)

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Q75
PYQ

Amongst the given options which of the following molecules/ion acts as a Lewis acid?

a

\({\mathrm{H}}_{2}\mathrm{O}\)

b

\(\mathrm{BF}_3\)

c

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

d

\({\mathrm{NH}}_{3}\)

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Q76
PYQ

\[\mathrm{PCl}_{5}(g) \rightleftharpoons \mathrm{PCl}_{3}(g)+\mathrm{Cl}_{2}(g) ; \mathrm{K}_{\mathrm{C}}=1.844\]

3.0 moles of \( \mathrm{PCl}_{5} \) is introduced in a \( 1 \mathrm{~L} \) closed reaction vessel at \( 380 \mathrm{~K} \). The number of moles \( \mathrm{PCl}_{5} \) at equilibrium is _____ \( \times 10^{-3} \). (Round off to the nearest integer)

a

1196

b

1296

c

1396

d

1496

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Q77
PYQ

The pH of a solution obtained by mixing 50 mL of 1 M HCl and 30 mL of 1 M NaOH is \(x\times {10}^{-4}\). The value of x is __________ . (Nearest integer)
\([\log 2.5=0.3979]\)

[JEE Main 2021, 31 Aug (Shift 2)]

a

6021

b

6031

c

6041

d

6051

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Q78
PYQ

Hydrolysis of sucrose is given by the following reaction.

Sucrose \( +\mathrm{H}_{2} \mathrm{O} \rightleftharpoons \) Glucose \( + \) Fructose

If the equilibrium constant \( \left(\mathrm{K}_{\mathrm{c}}\right) \) is \( 2 \times 10^{13} \) at \( 300 \mathrm{~K} \), the value of \( \Delta_{r} \mathrm{G}^{\mathrm{o}} \) at the same temperature will be :

[NEET 2020]

a

\( 8.314 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1} \times 300 \mathrm{~K} \times \ln \left(2 \times 10^{13}\right) \)

b

\( 8.314 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1} \times 300 \mathrm{~K} \times \ln \left(3 \times 10^{13}\right) \)

c

\( -8.314 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1} \times 300 \mathrm{~K} \times \ln \left(4 \times 10^{13}\right) \)

d

\( -8.314 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1} \times 300 \mathrm{~K} \times \ln \left(2 \times 10^{13}\right) \)

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Q79
PYQ

A homogeneous ideal gaseous reaction \( \mathrm{AB}_{2}(\mathrm{~g}) \rightleftharpoons \mathrm{A}(\mathrm{g})+2 \mathrm{~B}(\mathrm{~g}) \) is carried out in a 25 litre flask at \( 27^{\circ} \mathrm{C} \). The initial amount of \( \mathrm{AB}_{2} \) was 1 mole and the equilibrium pressure was \( 1.9 \mathrm{~atm} \). The value of \( \mathrm{K}_{P} \) is \( \mathrm{x} \times 10^{-2} \). The value of \( \mathrm{x} \) is _____________(Round off to nearest integer)\[

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

a

73

b

45

c

66

d

70

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Q80
PYQ

On decreasing the \(\mathrm{pH}\) from 7 to 2 , the solubility of a sparingly soluble salt (MX) of a weak acid (HX) increased from \({10}^{-4}\mathrm{mol}{\mathrm{L}}^{-1}\) to \({10}^{-3}\mathrm{mol}{\mathrm{L}}^{-1}\). The \({\mathrm{pK}}_{\mathrm{a}}\) of \(\mathrm{HX}\) is:

[JEE Advanced 2023, Paper-1]

a

3

b

4

c

5

d

2

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Q81
PYQ

Value of \( K_{P} \) for the equilibrium reaction, \( \mathrm{N}_{2} \mathrm{O}_{4}(\mathrm{~g}) \rightleftharpoons 2 \mathrm{NO}_{2}(\mathrm{~g}) \) at \( 288 \mathrm{~K} \) is 47.9 . The \( \mathrm{K}_{\mathrm{C}} \) for this reaction at same temperature is ___

(Nearest integer \( ) \quad\left(\mathrm{R}=0.083 \mathrm{~L}\right. \) bar \( \left.\mathrm{K}^{-1} \mathrm{~mol}^{-1}\right) \)

a

1

b

2

c

3

d

4

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Q82
PYQ

A solution of \({\mathrm{NH}}_{4}\mathrm{Cl}\) and \({\mathrm{NH}}_{3}\) has pH = 8.0. Which of the following hydroxides may be precipitated when this solution is mixed with equal volume of 0.2 M of metal ion.

a

\(\mathrm{Ba}{(\mathrm{OH})}_{2}({\mathrm{K}}_{\mathrm{sp}}=1.1\times {10}^{-4})\)

b

\(Mg{(\mathrm{OH})}_{2}({\mathrm{K}}_{\mathrm{sp}}=3.5\times {10}^{-4})\)

c

\(Fe{(\mathrm{OH})}_{2}({\mathrm{K}}_{\mathrm{sp}}=8.1\times {10}^{-16})\)

d

\(\mathrm{Ca}{(\mathrm{OH})}_{2}({\mathrm{K}}_{\mathrm{sp}}=2.1\times {10}^{-5})\)

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Q83
PYQ

The solubility product of \(\mathrm{Cr}(\mathrm{OH})_3\) at \(298 \mathrm{~K}\) is \(6.0 \times 10^{-31}\). The concentration of hydroxide ions in a saturated solution of \(\mathrm{Cr}(\mathrm{OH})_3\) will be:

a

\({\left(2.22\times {10}^{-31}\right)}^{1/4}\)

b

\({\left(18\times {10}^{-31}\right)}^{1/2}\)

c

\({\left(4.86\times {10}^{-29}\right)}^{1/4}\)

d

\({\left(18\times {10}^{-31}\right)}^{1/4}\)

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Q84
PYQ

The density of a monobasic strong acid (Molar mass \(24.2\mathrm{g}\) ) is \(1.21\mathrm{kg}/L\). The volume of its solution required for the complete neutralization of \(25\mathrm{mL}\) of \(0.24\mathrm{M}\mathrm{NaOH}\) is .............\(\times {10}^{-2}\mathrm{mL}\) (Nearest integer)

[JEE Main 2023, 25 Jan (Shift 1)]

a

11

b

12

c

13

d

14

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Q85
PYQ

Sulphurous acid \( \left(\mathrm{H}_{2} \mathrm{SO}_{3}\right) \) has
\( \mathrm{Ka}_{1}=1.7 \times 10^{-2} \) and \( \mathrm{Ka}_{2}=6.4 \) \( \times 10^{-8} \). The \( \mathrm{pH} \) of \( 0.588 \mathrm{~M} \mathrm{~H}_{2} \mathrm{SO}_{3} \) is........ (Round off to the nearest integer)

[JEE Main 2021, 16 Mar (Shift 2)]

a

1

b

3

c

5

d

7

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Q86
PYQ

The \( \mathrm{pK}_{\mathrm{b}} \) of dimethylamine and \( \mathrm{pK}_{\mathrm{a}} \) of acetic acid are \( 3.27 \) and \( 4.77 \) respectively at \( \mathrm{T}(\mathrm{K}) \). The correct option for the \( \mathrm{pH} \) of dimethylammonium acetate solution is:

a

\( 5.50 \)

b

\( 7.75 \)

c

\( 6.25 \)

d

\( 8.50 \)

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Q87
PYQ

For the reaction \( \mathrm{A}_{(\mathrm{g})} \rightleftharpoons \mathrm{B}_{(\mathrm{g})} \), the value of the equilibrium constant at \( 300 \mathrm{~K} \) and \( 1 \mathrm{~atm} \) is equal to 100.0 . The value of \( \Delta_{\mathrm{r}} \mathrm{G} \) for the reaction at \( 300 \mathrm{~K} \) and 1 atm in \( \mathrm{J} \mathrm{mol}^{-1} \) is \( -\mathrm{xR} \), where \( \mathrm{x} \) is

(Rounded off to the nearest integer)

\( \left(\mathrm{R}=8.31 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}\right. \) and \( \left.\ln 10=2.3\right) \)

a

1360

b

1370

c

1380

d

1390

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Q88
PYQ

The reaction rate for the reaction

\[\left[\mathrm{PtCl}_{4}\right]^{2-}+\mathrm{H}_{2} \mathrm{O} \rightleftharpoons\left[\mathrm{Pt}\left(\mathrm{H}_{2} \mathrm{O}\right) \mathrm{Cl}_{3}\right]^{-}+\mathrm{Cl}^{-}\]

was measured as a function of concentration of different species. It was observed that

\[\begin{array}{l}\frac{-\mathrm{d}\left[\left[\mathrm{PtCl}_{4}\right]^{2-}\right]}{\mathrm{dt}}=4.8 \times 10^{-5} \\ {\left[\left[\mathrm{PtCl}_{4}\right]^{2-}\right]-2.4 \times 10^{-3}\left[\left[\mathrm{Pt}\left(\mathrm{H}_{2} \mathrm{O}\right) \mathrm{Cl}_{3}\right]^{-}\right]\left[\mathrm{Cl}^{-}\right] \text {. }} \\\end{array}\]

where square brackets are used to denote molar concentration. The equilibrium constant \( \mathrm{K}_{\mathrm{C}}= \) _____\(\text{x}{10}^{-2}\). (Nearest integer)

a

1

b

2

c

3

d

4

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Q89
PYQ

Given below are two statements.

Statement-I: In the titration between strong acid and weak base, methyl orange is suitable as an indicator.

Statement-II: For titration of acetic acid with \( \mathrm{NaOH} \), phenolphthalein is not a suitable indicator.

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


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

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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Q90
PYQ

A mixture of 1 mole of \({\mathrm{H}}_{2}\mathrm{O}\) and 1 mole of CO is taken in a 10 litre container and heated to 725 K. At equilibrium 40% of water by mass reacts with carbon monoxide according to the equation :

\(\mathrm{CO}(\mathrm{g})+{\mathrm{H}}_{2}\mathrm{O}(\mathrm{g})\to {\mathrm{CO}}_{2}(\mathrm{g})+{\mathrm{H}}_{2}(\mathrm{g})\)

The value of \({\mathrm{K}}_{\mathrm{C}}\times {10}^{2}\) for the reaction is_______.

(KC - Equilibrium constant) (Nearest integer)

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

a

11

b

22

c

33

d

44

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Q91
PYQ

3g of acetic acid is added to 250mL of 0.1 M HCL and the solution made up to 500 mL. To 20 mL of this solution \(1/2\mathrm{mL}\) of 5 M NaOH is added.

The pH of the solution is___________(round off to the nearest integer)

[Given: pKa of acetic acid =4.75, molar mass of acetic acid =60 g/ mol, log 3=0.4771] Neglect any changes in volume.
[JEE Main 2020, 7 Jan (Shift 2)]

a

4

b

5

c

6

d

7

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Q92
PYQ

Given below are two statements.

Statement-I: In the titration between strong acid and weak base, methyl orange is suitable as an indicator.

Statement-II: For titration of acetic acid with \( \mathrm{NaOH} \), phenolphthalein is not a suitable indicator.

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

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

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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Q93
PYQ

An acidified solution of \(0.05 M Zn ^{2+}\) is saturated with \(0.1 M H _2 S\). What is the minimum molar concentration (M) of \(H ^{+}\)required to prevent the precipitation of \(ZnS\) ?

Use \(K _{ sp }( ZnS )=1.25 \times 10^{-22}\) and overall dissociation constant of \(H _2 S , K _{ NET }= K _1 K _2=1 \times 10^{-21}\)
[JEE Advanced 2020, Paper-2]

a

0.2

b

0.1

c

2

d

0.35

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Q94
PYQ

The dissociation constant of acetic is \(x\times {10}^{-5}\). When \(25\mathrm{mL}\) of \(0.2\mathrm{M}{\mathrm{CH}}_{3}\mathrm{COONa}\) solution is mixed with \(25\mathrm{mL}\) of \(0.02\mathrm{M}{\mathrm{CH}}_{3}\mathrm{COOH}\) solution, the \(\mathrm{pH}\) of the resultant solution is found to be equal to 5 . The value of x is

[JEE Main 2023, 24 Jan (Shift 1)]

a

9

b

10

c

11

d

12

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Q95
PYQ

Water decomposes at \(2300 \mathrm{~K}\)
\({\mathrm{H}}_{2}\mathrm{O}(\mathrm{g})\to {\mathrm{H}}_{2}(\mathrm{g})+\frac{1}{2}{\mathrm{O}}_{2}(\mathrm{g})\)

The percent of water decomposing at \(2300 \mathrm{~K}\) and \(1 \mathrm{bar}\) is......... (Nearest integer).
Equilibrium constant for the reaction is \(2 \times 10^{-3}\) at \(2300 \mathrm{~K}\).

a

1

b

2

c

3

d

4

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Q96
PYQ

Which one of the following molecular hydrides acts as a Lewis acid?

a

\(N{H}_{3}\)

b

\({H}_{2}O\)

c

\({B}_{2}{H}_{6}\)

d

\(C{H}_{4}\)

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Q97
PYQ

Millimoles of calcium hydroxide required to produce 100 mL of the aqueous solution of pH =12 is x \(\times {10}^{-1}\). The value of \(\mathrm{x}\) is ________(Nearest integer).

Assume complete dissociation.

[JEE Main 2023, 29 Jan (Shift 1)]

a

3

b

4

c

5

d

6

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Q98
PYQ

\(\mathrm{A}(\mathrm{g})⇌2\mathrm{B}(\mathrm{g})+\mathrm{C}(\mathrm{g})\)

For the given reaction, if the initial pressure is \(450\mathrm{mm}\) Hg and the pressure at time t is \(720\mathrm{mmHg}\) at a constant temperature T and constant volume V. The fraction of Ag decomposed under these conditions is \(\mathrm{x}\times {10}^{-1}\). The value of x is (nearest integer)

[JEE Main 2023, 10 Apr (Shift 2)]

a

1

b

2

c

3

d

4

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Q99
PYQ

4.5 moles each of hydrogen and iodine is heated in a sealed ten litre vessel. At equilibrium, 3 moles of HI were found. The equilibrium constant for

\({\mathrm{H}}_{2}(\mathrm{g})+{\mathrm{I}}_{2}(\mathrm{g})⇌2\mathrm{HI}(\mathrm{g})\) is _____

[JEE Main 2023, 11 Apr (Shift 2)]

a

1

b

2

c

3

d

4

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Q100
PYQ

The effect of addition of helium gas to the following reaction in equilibrium state, is:

\({\mathrm{PCI}}_{5}(\mathrm{g})⇌{\mathrm{PCl}}_{3}(\mathrm{g})+{\mathrm{Cl}}_{2}(\mathrm{g})\)

[JEE Main 2023, 1 Feb (Shift 2)]

a

the equilibrium will shift in the forward direction and more of \({\mathrm{Cl}}_{2}\) and \({\mathrm{PCl}}_{3}\) gases will be produced.

b

the equilibrium will go backward due to suppression of dissociation of \({\mathrm{PCl}}_{5}\).

c

helium will deactivate \({\mathrm{PCl}}_{5}\) and reaction will stop.

d

addition of helium will not affect the equilibrium.

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Q101
PYQ

The solubility of \(\mathrm{Ca}(\mathrm{OH}{)}_{2}\) in water is :
[Given : The solubility product of \(\mathrm{Ca}(\mathrm{OH}{)}_{2}\) in water \(=5.5\times {10}^{-6}\) ]

[JEE Main 2021, 25 Feb (Shift 2)]

a

\(1.11\times {10}^{-6}\)

b

\(1.77\times {10}^{-6}\)

c

\(1.77\times {10}^{-2}\)

d

\(1.11\times {10}^{-2}\)

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Q102
PYQ

An acidic buffer is obtained on mixing

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

a

\(100\mathrm{mL}\) of \(0.1\mathrm{M}\mathrm{HCI}\) and \(200\mathrm{mL}\) of \(0.1\mathrm{M}\mathrm{NaCI}\)

b

\(100\mathrm{mL}\) of \(0.1\mathrm{M}\mathrm{HCl}\) and \(200\mathrm{mL}\) of \(0.1\mathrm{M}\) \({\mathrm{CH}}_{3}\mathrm{COONa}\)

c

\(100\mathrm{mL}\) of \(0.1\mathrm{M}{\mathrm{CH}}_{3}\mathrm{COOH}\) and \(100\mathrm{mL}\) of \(0.1\mathrm{M}\) \(\mathrm{NaOH}\)

d

\(100\mathrm{mL}\) of \(0.1\mathrm{M}{\mathrm{CH}}_{3}\mathrm{COOH}\) and \(200\mathrm{mL}\) of \(0.1\mathrm{M}\) \(\mathrm{NaOH}\)

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Q103
PYQ

The gas phase reaction,

\[2 \mathrm{~A}(\mathrm{~g}) \rightleftharpoons \mathrm{A}_{2}(\mathrm{~g})\]

at \( 400 \mathrm{~K} \) has \( \Delta \mathrm{G}^{0}=+25.2 \mathrm{~kJ} \mathrm{~mol}^{-1} \).

The equilibrium constant \( \mathrm{K}_{\mathrm{C}} \) for this reaction is ____ \( \times 10^{-2} \) (Round off to the nearest integer) (Use : \( \mathrm{R}=8.3 \mathrm{~J} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}, \ln 10=2.3, \log _{10} 2=0.30,1 \mathrm{~atm} \) - \( =1 \) bar \( )(\operatorname{antilog}(-0.3)=0.501) \)

[JEE Main 2021, 18 Mar (Shift 2)]

a

100

b

200

c

300

d

400

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Q104
PYQ

In order to prepare a buffer solution of \( \mathrm{pH} = ~5.74 \), sodium acetate is added to acetic acid. If the concentration of acetic acid in the buffer is \( 1.0 \mathrm{~M} \), the concentration of sodium acetate in the buffer is _____M.

(Round off to the nearest integer).

[Given; \( \mathrm{pK}_{\mathrm{a}}( \) acetic acid \( )=4.74 \) ]

[JEE Main 2021, 18 Mar (Shift 1)]

a

8

b

9

c

10

d

11

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Q105
PYQ

At \( 310 \mathrm{~K} \), the solubility of \( \mathrm{CaF}_{2} \) in water is \( 2.34 \times 10^{-3} \) \( \mathrm{g} / 100 \mathrm{~mL} \). The solubility product of \( \mathrm{CaF}_{2} \) is __________ \({10}^{-12}{\left(\mathrm{mol}/\mathrm{L}\right)}^{3}\).

Given molar mass: \( \mathrm{CaF}_{2}=78 \mathrm{~g} \mathrm{~mol}^{-1} \)

a

108

b

208

c

308

d

408

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Q106
PYQ

The number of correct statements involving equilibria in physical process from the following is

(i) Equilibrium is possible only in a closed system at a given temperature.

(ii) Both the opposing processes occur at the same rate.

(iii) When equilibrium is attained at a given temperature, the value of all its parameters became equal.

(iv) For dissolution of solids in liquids, the solubility is constant at a given temperature

[JEE Main 2023, 10 Apr (Shift 1)]

a

1

b

2

c

3

d

4

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Q107
PYQ

25.0 mL of \(0.050\mathrm{M}\mathrm{Ba}{\left({\mathrm{NO}}_{3}\right)}_{2}\) is mixed with \(25.0\mathrm{mL}\) of \(0.020\mathrm{M}\mathrm{NaF}.{\mathrm{K}}_{\mathrm{sp}}\) of \({\mathrm{BaF}}_{2}\) is \(0.5\times {10}^{-6}\) at \(298\mathrm{K}\). The ratio of \(\left[{\mathrm{Ba}}^{2+}\right]{\left[{\mathrm{F}}^{-}\right]}^{2}\) and \({\mathrm{K}}_{\mathrm{sp}}\) is...................... (Nearest integer)

[JEE Main 2023, 13 Apr (Shift 1)]

a

5

b

6

c

14

d

10

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Q108
PYQ

Two salts \( A_{2} X \) and \( M X \) have the same value of solubility product of \( 4.0 \times 10^{-12} \). The ratio of their molar solubilities i.e. \( \frac{S\left(A_{2} X\right)}{S(M X)}= \)___________

(Round off to the nearest integer).

[JEE Main 2021, 16 Mar (Shift 1)]

a

40

b

50

c

60

d

80

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Q109
PYQ

Given below are two statements:

Statement I: Methyl orange is a weak acid.

Statement II: The benzenoid form of methyl orange is more intense / deeply coloured than the quinonoid form.

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

[JEE Main 2023, 08 Apr (Shift 2)]

a

Statement- I is correct but Statement -II is incorrect.

b

Statement -I is incorrect but Statement - II is correct.

c

Both Statement -I and Statement -II are incorrect.

d

Both Statement -I and Statement II are correct.

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Q110
PYQ

\(20\mathrm{mL}\) of 0.1 M NaOH is added to \(50\mathrm{mL}\) of 0.1 M acetic acid solution. The pH of the resulting solution is _________\(\times {10}^{-2}\) (Nearest integer)

Given : \({\mathrm{pK}}_{\mathrm{a}}\left({\mathrm{CH}}_{3}\mathrm{COOH}\right)=4.76\)

\(\log 2=0.30\)

\(\log 3=0.48\)

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

a

455

b

458

c

490

d

340

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Q111
PYQ

The molar solubility of \( \mathrm{Zn}(\mathrm{OH})_{2} \) in \( 0.1 \mathrm{~M} \mathrm{~NaOH} \) solution is \( x \times 10^{-18} \mathrm{M} \). The value of \( x \) is ___________. (Nearest integer)

(Given: The solubility product of \( \mathrm{Zn}(\mathrm{OH})_{2} \) is \( 2 \times 10^{-20} \) )

[JEE Main 2021, 1 Sep (Shift 2)]

a

2

b

4

c

6

d

8

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Q112
PYQ

For reaction : \({\mathrm{SO}}_{2}(\mathrm{g})+\frac{1}{2}{\mathrm{O}}_{2}(\mathrm{g})⇌{\mathrm{SO}}_{3}(\mathrm{g})\)

KP = 2 × 1012 at 27°C and 1 atm pressure. The KC for the same reaction is …… × 1013. (Nearest integer)

(Given R = 0.082L atm K–1 mol–1)

a

1

b

2

c

3

d

4

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