🏫 Board🧪 Chemistry

Chemical Reactions and Equations

7 Board Chemistry previous year questions on Chemical Reactions and Equations — options free on every question; 1 include the answer & explanation free, the rest unlock with PYQ Pass.

Q1 FREE PREVIEW

What is the chemical name of slaked lime ?

a

Calcium Oxychloride

b

Calcium Chloride

c

Calcium Oxide

d

Calcium Hydroxide

✓ Correct answer: d)

Calcium Hydroxide

Explanation

The chemical name of slaked lime is calcium hydroxide (Ca(OH)₂).

Explanation:

  • When quick lime (CaO) is mixed with water, it reacts as:
    \([CaO+{H}_{2}O\to Ca(OH{)}_{2}]\)

  • The product Ca(OH)₂ is called slaked lime.

Chemical Name Formula Common Name
Calcium Oxychloride \({\mathrm{CaOCl}}_{2}\) Bleaching Powder
Calcium Chloride \({\mathrm{CaCl}}_{2}\) Drying Agent
Calcium Oxide CaO Quicklime
Calcium Hydroxide \(\mathrm{Ca}{(\mathrm{OH})}_{2}\) Slaked lime
Q2

Which of the following reactions is an example of decomposition reaction?

a

\({\mathrm{H}}_{2}+{\mathrm{I}}_{2}\to 2\mathrm{HI}\)

b

\({\mathrm{NH}}_{4}\mathrm{CNO}\to {\mathrm{H}}_{2}{\mathrm{NCONH}}_{2}\)

c

\(\mathrm{NaOH}+\mathrm{HCl}\to \mathrm{NaCl}+{\mathrm{H}}_{2}\mathrm{O}\)

d

\(2{\mathrm{KClO}}_{3}\to \mathrm{KCl}+3{\mathrm{O}}_{2}\)

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Q3

Reaction : \(2{\mathrm{PbO}}_{(\mathrm{s})}+{\mathrm{C}}_{(\mathrm{s})}\to 2{\mathrm{Pb}}_{(\mathrm{s})}+{\mathrm{CO}}_{2(\mathrm{g})}\)

Statements: i) Lead is getting oxidised.
ii) Carbon dioxide is getting oxidised.
iii) Carbon is getting oxidised.
iv) Lead oxide is getting reduced.

True statement for above reaction is -

a

i) and ii)

b

Only i)

c

Only ii)

d

iii) and iv)

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Q4

Reaction: \(2{\mathrm{PbO}}_{(\mathrm{s})}+{\mathrm{C}}_{(\mathrm{s})}\to 2{\mathrm{Pb}}_{(\mathrm{s})}+{\mathrm{CO}}_{2(\mathrm{g})}\)

Statements: i) Lead is getting oxidised.
ii) Carbon dioxide is getting oxidised.
iii) Carbon is getting oxidised.
iv) Lead oxide is getting reduced.

True statement for above reaction is -

a

(i) and (ii)

b

Only (i)

c

Only ii

d

(iii) and iv)

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Q5

Number of electrons present in M shell of phosphorous atom is -

a

3

b

5

c

6

d

7

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Q6

\(\mathrm{Fe}+{\mathrm{H}}_{2}\mathrm{O}\to {\mathrm{Fe}}_{3}{\mathrm{O}}_{4}+{\mathrm{H}}_{2}\)

The coefficient of Fe in the balanced equation of the above reaction will be;

a

1

b

2

c

3

d

4

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Q7

SECTION - A

Multiple Choice Questions (Q. No. 1 - 6 ) : - Each Q. 1 Mark

\(\mathrm{KOH}+{\mathrm{H}}_{2}{\mathrm{SO}}_{4}\to {\mathrm{K}}_{2}{\mathrm{SO}}_{4}+{\mathrm{H}}_{2}\mathrm{O}\)

The above reaction is an example of a

a

Combination reaction

b

Double displacement reaction

c

Decomposition reaction

d

Displacement reaction

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