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CHEMICAL REACTIONS AND EQUATIONS

Total questions: 10

Worksheet time: 9mins

Name
Class
Date
1.

Which of the following gases can be used for storage of fresh sample of an oil for a long time?

a)

Carbon dioxide or oxygen

b)

Nitrogen or oxygen

c)

Carbon dioxide or helium

d)

nitrogen

2.

Which of the following statements about the given reaction are correct?
3Fe(s) + 4H2O(g) \rightarrow   Fe3O4(s) + 4H2(g)
(i) Iron metal is getting oxidised
(ii) Water is getting reduced
(iii) Water is acting as reducing agent
(iv) Water is acting as oxidising agent

a)

(i), (ii) and (iii)

b)

(iii) and (iv)

c)

(i), (ii) and (iv)

d)

(ii) and (iv)

3.

Three beakers labelled as A, B and C each containing 25 mL of water were taken. A small amount of NaOH, anhydrous CuSO4 and NaCl were added to the beakers A, B and C respectively. It was observed that there was an increase in the temperature of the solutions contained in beakers A and B, whereas in case of beaker C, the temperature of the solution falls. Which one of the following statement(s) is(are) correct?

(i) In beakers A and B, exothermic process has occurred.

(ii) In beakers A and B, endothermic process has occurred. (iii) In beaker C exothermic process has occurred.

(iv) In beaker C endothermic process has occurred.

a)

(i) only

b)

(ii) only

c)

(i) and (iv)

d)

(ii) and (iii)

4.

Which among the following is(are) double displacement
reaction(s)?
(i) Pb + CuCl2  \rightarrow   PbCl2 + Cu
(ii) Na2SO4 + BaCl2  \rightarrow   BaSO4 + 2NaCl
(iii) C + O2  \rightarrow  CO2
(iv) CH4 + 2O2  \rightarrow   CO2 + 2H2O

a)

(i) and (iv)

b)

(ii) only

c)

(i) and (ii)

d)

(iii) and (iv)

5.

The following reaction is used for the preparation of oxygen gas in the laboratory
2KClO3 (s) + Heat --Catalyst \rightarrow   2KCl (s) + 3O2 (g)
Which of the following statement(s) is(are) correct about the reaction?

a)

It is a decomposition reaction and endothermic in nature

b)

It is a combination reaction

c)

It is a decomposition reaction and accompanied by release of heat

d)

It is a photochemical decomposition reaction and exothermic in nature

6.

Barium chloride on reacting with ammonium sulphate forms barium sulphate and ammonium chloride. Which of the following correctly represents the type of the reaction involved?

(i) Displacement reaction

(ii) Precipitation reaction

(iii) Combination reaction

(iv) Double displacement reaction

a)

(i) only

b)

(ii) only

c)

(iv) only

d)

(ii) and (iv)

7.

Which is the correct atom count for the reactant side of the chemical equation? Balance the chemical reaction and then count the atoms

CH4 + O2 -> CO2 + H2O

a)

C=4

H=4

O=4

b)

C=1

H=4

O=2

c)

C=1

H=4

O=2

d)

C=1

H=4

O=4

8.

What is the oxidation number Mn in KMnO4 ?

a)

4

b)

3

c)

7

d)

1

9.

Which of the following sentences are correct about reduction?

*Check all the correct answers

a)

Removal of oxygen

b)

Gain of electrons

c)

Decreases in oxidation nuber of an element in a reaction

d)

-ve valency of a species increases in a reaction

10.

What is the correct increasing order of oxidation state of nitrogen in following compounds:

NH3, N2, NH2OH, NO2

a)

NH3 < NO2 < N2 < NH2OH

b)

NO2 < NH3 < NH2OH < NH3

c)

NH3 < NH2OH < NO2 < N2

d)

NH3 < NH2OH < N2 < NO2