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Worksheets

Chemical Reactions & Equations

Total questions: 25

Worksheet time: 16mins

Name
Class
Date
1.

Magnesium ribbon is rubbed before burning because it has a coating of

a)

basic magnesium carbonate

b)

basic magnesium oxide

c)

basic magnesium sulphide

d)

basic magnesium chloride

2.

Calcium oxide reacts vigorously with water to produced slaked lime

CaO + H2O ---> Ca(OH)2

a)

Combination reaction

b)

Exothermic reaction

c)

Endothermic reaction

d)

Combination & Exothermic

e)

Combination & Endothermic

3.

Which of the following displacement reaction?

a)

MgCo3 ---> MgO + CO2

b)

2H2 + 2H2O ---> 2H2O

c)

2Na + 2H2O ---> 2NaOH + H2

d)

2Pb(NO3)2 ---> 2PbO + 4NO2 + O2

4.

When green color ferrous sulphate crystals are heated, the color of crystal changes because

a)

loses water of crystalline

b)

decomposed to ferric oxide

c)

forms SO2

d)

forms SO3

5.

A dil. ferrous sulphate solution was gradually added to the beaker containing acidified permanganate solution. The light purple color of the solution fades and finally disappears. Which of the following is the correct explanation?

a)

KMnO4 is an oxidizing agent, it oxides FeSO4

b)

FeSO4 is an oxidizing agent, it oxides KMnO4

c)

Color disappears due to dilution, no reaction involved

d)

KMnO4 is an unstable compound and decomposes in the presence of FeSO4 to a colorless compund

6.

When SO2 gas passed through saturated solution of H2S, which of the following reaction occurs?

a)

SO2 + 2H2S ---> 2H2O + 3S

b)

SO2 + 2H2S ---> H2O + 3S

c)

SO2 + H2S ---> H2O + S

d)

SO2 + H2O ---> H2 + SO3

7.

A substance X is used in white - washing and is obtained by heating limestone in the absence of air. Identify X

a)

Cao

b)

CaCO3

c)

CaOCl2

d)

Ca(OH)2

8.

MnO2 + 4 HCl ---> MnCl2 + 2H2O + Cl2

Identify the substances oxidized in the above reaction/equation

a)

MnCl2

b)

HCl

c)

H2O

d)

MnO2

9.

Which of the following is the exothermic reaction?

i. Reaction of water with quick lime.

ii. Dilution of an acid

iii. Evaporation of water

iv. Sublimation of camphor

a)

i & iv

b)

ii & iv

c)

i & ii

d)

ii & iii

10.

Which of the following statement about the reaction are correct?

3Fe + 4H2O ---> Fe2O4 + 4H2

i. iron metal getting oxidized

ii. Water is getting oxidized

iii. Water is acting as reducing agent

iv. Water is acting as oxidizing agent

a)

i, ii, iii

b)

iii, iv

c)

i, ii, iv

d)

ii , iv

11.

During an experiment, Monika takes lead nitrite in a test tube and adds potassium iodide. What will she observe in a test tube?

a)

Yellow ppt

b)

Red ppt

c)

Green ppt

d)

Nothing will happen

12.

Given below the balance chemical equation for the thermal decomposition of lead nitrite:

2Pb(NO3)2 ---> 2PbO + 4NO2 + O2

Which of the following information does the coefficients of PbO and NO2 in the equation (2 and 4 respectively) tell us?

a)

The ratio of densities of two substances

b)

The ratio of the mass produced of two substances

c)

The ratio of number of atoms in the two substances

d)

The ratio of the number of moles produced of the two substances

13.

Which of the following is the example of simple displacement?

a)

Electrolysis of water

b)

Burning of methane

c)

Reaction of metal with acid

d)

Reaction of two salt solution to form a ppt

14.

What will happen of calcium oxide added to water?

a)

Formation of carbon di oxide

b)

Formation of oxygen

c)

Formation of calcium hydroxide

d)

formation of quick lime

15.

When hydrogen sulphide gas is passed through a blue solution of copper sulphate, a black ppt of copper sulphide is obtained and the sulphuric acid is formed. The reaction is an example of

a)

Combination

b)

Displacement

c)

Decomposition

d)

Double - Displacement

16.

During a experiment, Narendra takes a 2g of lead nitrate powder in the boiling tube and hold the boiling tube with a pair of tongs. He then heats it over the flame. After a few seconds, he sees X color fumes coming out of the tube, So what is the color of the fumes?

a)

Pink

b)

Reddish brown

c)

Red

d)

Colourless

17.

Why is silver chloride is kept in dark bottle?

a)

To prevents it from rats

b)

To prevents it from decomposition into silver and chloride

c)

To make it visible

d)

To show it as dangerous chemical

18.

If an iron nail is dipped in a solution of copper sulphate for 20min and the color of the iron nail becomes brownish, what is the color change of the copper sulphate after 20min?

a)

Color of solution becomes green

b)

Color of solution becomes red

c)

Color of solution becomes brighter

d)

Color of solution becomes fade

19.

Electrolysis of water is a decomposition reaction. The mole ratio of hydrogen and oxygen gases liberated during electrolysis of water is

a)

1:1

b)

2:1

c)

4:1

d)

1:2

20.

Which of the following is an endothermic reaction?

i. Dilution of sulphuric acid

ii. Sublimation of dry ice

iii. condensation of water vapors

iv. Evaporation of water

a)

i only

b)

ii only

c)

i, iv

d)

ii, iv

21.

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

i. Displacement

ii. Combination

iii. PPt (precipitation)

iv. Double displacement

a)

i, iv

b)

ii, iii

c)

iii, iv

d)

i, ii

22.

A: Calcium carbonate when heated gives calcium oxide and water

R: On heating CaCO3 , decomposition reaction take place

(a)  

23.

A: Stannous chloride is a powerful oxidizing agent which oxidises mercuric chloride to mercury.

R: Stannous chloride gives grey ppt with mercuric chloride, but stannous chloride does not do so

(a)  

24.

A: To dilute sulphuric acid, acid is added to water and not water to acid.

R: Specific heat of water is quite large

(a)  

25.

A: Sodium metal is stored under Kerosene

R: Metallic sodium melts when exposed to air

(a)