Master Class 10 Science – Chemical Reactions and Equations with Our MCQ Mock Test!

Are you confident about balancing equations, identifying types of reactions, and predicting products? Test your knowledge with this exclusive MCQ-based mock test on Chemical Reactions and Equations. Designed as per the Class 10 Science syllabus, this test covers all the key concepts – from different types of chemical reactions (combination, decomposition, displacement, double displacement) to oxidation and reduction, and balancing equations with accuracy.

This mock test will not only help you revise important topics but also give you an exam-like experience that sharpens speed, accuracy, and problem-solving skills. Perfect for practice before school tests, board exams, or quick self-assessment.

Attempt now to check your preparation level and make Chemical Reactions & Equations your strongest chapter!

1. A student notices that new hammer made of iron is shiny while an old one kept in the tool box has a reddish brown deposit over it. What does the change in colour of hammer indicate?

Effect of moisture on metals

Iron hammer turns brown after sometime.

Effects of kept in a box for longer duration.

Iron changes colour when kept with other tools.

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

It is a decomposition reaction and endothermic in nature

It is a combination reaction

It is a decomposition reaction and accompanied by release of heat

It is a photochemical decomposition reaction and exothermic in nature

3. Which one of the following processes involve chemical reactions ?

Storing of oxygen gas under pressure in a gas cylinder

Liquefaction of air

Keeping petrol in a china dish in the open

Heating copper wire in presence of air at high temperature

4. The brown gas evolved on heating of copper nitrate is

NO2

The Step 1 and Step 2 respectively are

endothermic, exothermic

both endothermic

both exothermic

exothermic, endothermic

6. Reema took 5 mL of lead nitrate solution in a beaker and added approximately 4 mL of KI solution to it. What would she observe?

The solution turned red.

Yellow precipitate was formed.

White precipitate was formed.

The reaction mixture becomes hot.

7. Which of the following involves combination of two elements ?

N2(g) + 3H2(g) → 2NH3(g)

CaO(s) + CO2(g) → CaCO3(g)

2SO2(g) + O2(g) → 2SO3(g)

NH3(g) + HCl(g) → NH4Cl(s)

8. Which of the following reactions will not take place?

Zn + CuSO4 → ZnSO4 + Cu

2KBr + Cl2 → KCl + Br2

Zn + MgSO4 → ZnSO4 + Mg

Mg + FeSO4 → MgSO4 + Fe

9. In the reaction Hg₂Cl₂ + Cl₂ → 2HgCl₂
The reducing agent is

Hg2Cl2

Cl2

HgCl2

Both Cl2 and HgCl2

10. In which of the following chemical equations, the abbreviations represent the correct states of the reactants and products involved at reaction temperature ?

2H2(l) + O2(l) → 2H2O(g)

2H2 (g) + O2(l) → 2H2O(l)

2H2 (g) + O2 (g) → 2H2O(l)

2H2 (g) + O2 (g) → 2H2O(g)

11. Burning Magnesium ribbon is brought in the gas jar of carbon dioxide. Which of the following is correct ?
(i) It keeps on burning
(ii) It gets extinguished
(iii) Although CO₂ is non-supporter of combustion but burning magnesium breaks CO₂ into carbon and oxygen, oxygen helps in burning.
(iv) Carbon dioxide is supporter of combustion.

(i) and (iv)

(i) and (iii)

(i) and (ii)

(iii) and (iv)

12.

Direction: In the following Question, the Assertion and Reason have been put forward. Read the statements carefully and choose the correct alternative from the following:

Assertion: Silver bromide decomposition is used in black and white photography.

Reason: Light provides energy for this exothermic reaction.

Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion.

The Assertion and the Reason are correct but the Reason is not the correct explanation of the Assertion.

Assertion is true but the Reason is false.

Assertion is false but the Reason is true.

13. Which of the following is precipitation as well as double displacement reaction?

NaOH(aq) + HNO3(aq) → NaNO3(aq) + H2O(l)

Cu(s) + 2AgNO3(aq) → Cu(NO3)2(aq) + 2Ag(s)

2Hg(s) + O2(g) 2HgO(s)

FeCl3(aq) + 3NH4OH(aq) → Fe(OH)3(s) + 3NH4Cl(aq)

14. A student learns that food companies fill bags of chips with nitrogen gas. What is the purpose of packing it with N₂ gas?

It prevents rancidity of chips.

It keeps mosquitos away from chips.

It keeps the chips dry if pack falls in water.

Prevents chips from spilling out when pack is opened.

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

1 : 1

2 : 1

4 : 1

1 : 2

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

Carbon dioxide or oxygen

Nitrogen or oxygen

Carbon dioxide or helium

Helium or nitrogen

17. 2AgI(s) 2Ag(s) + I₂(g)
The colour of iodine is

Green

Purple

Brown

Pink

18.

Which of the following is correct observation of the reaction shown in above set up?

Brown powder of magnesium oxide is formed.

Colourless gas which turns lime water milky is evolved.

Magnesium ribbon burns with brilliant white light.

Reddish brown gas with a smell of burning sulphur has evolved.

19. Which of the following is a NECESSARY condition for ALL chemical reactions?

The reactants should be in the same state.

Energy should be supplied to the reactants.

The reactants should be at the same temperature.

There should be physical contact between the reactants.

20. Which of the following is an example of simple displacement?

The electrolysis of water

The burning of methane

The reaction of a metal with an acid

The reaction of two salt solutions to form a precipitate

21. A student notices her jewellary turned dull and had grey black film over it after wearing for a few months. What results in the change in its colour?

Dust deposit over the jewellery which changes its colour.

The jewellary comes in contact with air, moisture, acids and corrodes.

The polish over the jewellary was removed after wearing for few months.

Silver breaks due to wear and tear and turns its colour change due to rusting.

22. MnO₂ + 4HCl → MnCl₂ + H₂O + Cl₂
The oxidising agent is

MnO2

HCl

MnCl2

Ag + Zn(NO3)3

23. A student notices that bread kept out has a green coating over it after few days. What explains the reason for the student’s observation?

The oils of bread oxidises and cause rancidity.

Bread comes in contact with atmospheric moisture and corrodes.

The oils in the bread reduces and causes change in colour of bread.

Comes in contact with the atmospheric nitrogen and layer deposit over it.

24. Identify ‘x’, ‘y’ and ‘z’ in the following balanced reaction
xPb(NO₃)₂(s) yPbO(s) + zNO₂(g) + O₂(g)

2, 4, 2

2, 2, 4

2, 4, 4

4, 2, 2

25. Zinc reacts with silver nitrate to form which compounds?

Zn(NO3)2 + Ag

ZnNO3 + Ag

AgNO3 + Zn(NO3)2

Ag + Zn(NO3)3

26. Which of the following is (are) an endothermic process(es)?

(i) Dilution of sulphuric acid
(ii) Sublimation of dry ice
(iii) Condensation of water vapours
(iv) Evaporation of water

(i) and (iii)

(ii) only

(iii) only

(ii) and (iv)

27.

Direction: In the following Question, the Assertion and Reason have been put forward. Read the statements carefully and choose the correct alternative from the following:

Assertion: A reaction in which a substance is decomposed into two or more substances is known as decomposition reaction.

Reason: The decomposition of a substance is impossible without supplying energy.

Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion.

The Assertion and the Reason are correct but the Reason is not the correct explanation of the Assertion.

Assertion is true but the Reason is false.

Assertion is false but the Reason is true.

28. Given below is the balanced chemical equation for the thermal decomposition of lead nitrate.

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?

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

The ratio of the number of atoms in the two substances.

The ratio of the mass produced of the two substances.

The ratio of the densities of the two substances.

29. What is observed when a solution of potassium iodide is added to silver nitrate solution?

No reaction takes place

White precipitate of silver iodide is formed

yellow precipitate of AgI is formed

AgI is soluble in water.

30. Direction: In the following Question, the Assertion and Reason have been put forward. Read the statements carefully and choose the correct alternative from then following:

Assertion: Combustion reaction is also called exothermic oxidation reaction.

Reason: In a combustion reaction O₂ is added and heat is released.

Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion.

The Assertion and the Reason are correct but the Reason is not the correct explanation of the Assertion.

Assertion is true but the Reason is false.

Assertion is false but the Reason is true.

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