CBSE Class 10 Science Chemical Reactions and Equations MCQs Set F

Question. A substance A reacts with another substance B to produce the product C and a gas D. If a mixture of the gas D and ammonia is passed through an aqueous solution of C, baking soda is formed. The substances A and B are
(a) HCl and NaOH
(b) HCl and Na₂CO₃
(c) Na and HCl
(d) Na₂CO₃ and H₂O

Answer: B

Question. A redox reaction is one in which-
(a) both the substance are reduced
(b) both the substance are oxidised
(c) an acid is neutralised by the base
(d) one substance is oxidised while the other is reduced D

Answer: D

Question. Black and white photography uses-
(a) decomposition of silver chloride
(b) decomposition of silver bromide
(c) both
(d) none of the options

Answer: B

Question. In the equation, NaOH+ HNO₃→ HNO₃→H₂O +nitric acid is acting as-
(a) an oxidising agent
(b) an acid
(c) a nitrating agent
(d) a dehydrating agent

Answer: B

Question. CuO + H₂ → H₂O + Cu, reaction is an example of –
(a) redox reaction
(b) synthesis reaction
(c) neutralisation
(d) analysis reaction

Answer: A

Question. Zn2+(aq) + 2e– → Zn(s). This is –
(a) oxidation
(b) reduction
(c) redox reaction
(d) none of the options

Answer: B

Question. A student took solid quick lime in a china dish and added a small amount of water. He heard
(a) a popping sound
(b) a crackling sound
(c) a hissing sound
(d) no sound at all

Answer: B

Question. The colour of the gas evolved on heating solid lead nitrate is
(a) Yellow
(b) Brown
(c) greenish-yellow
(d) green

Answer: B

Question. Which of the following observation help(s) us to determine that a chemical change has taken place?
(a) Change in temperature.
(b) Change in colour.
(c) Evolution of a gas.
(d) All of these.

Answer: D

Question. A dilute ferrous sulphate solution was gradually added to the beaker containing acidified potassium permanganate solution. The light purple colour of the solution fades and finally disappears. Which of the following is the correct explanation for the observation?
(a) KMnO₄ is an oxidising agent, it oxidises FeSO₄
(b) FeSO4 acts as an oxidising agent and oxidises KMnO₄
(c) The colour disappears due to dilution; no reaction is involved
(d) KMnO₄ is an unstable compound and decomposes in presence of FeSO₄ to a colourless compound.

Answer: A

Question. The following reaction is used for preparation of oxygen gas in the laboratory:
2KClO₃ (s) Heat /Catalyst2KCl(s) + 3O₂ (g)
Which of the following statements is 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 is accompanied by release of heat.
(d) It is a photo chemical decomposition reaction and exothermic in nature.

Answer: A

Question. The following reaction is an example of a 4NH₃ (g) + 5O₂ (g) 4NO(g)+ 6H₂O(g)
(i) displacement reaction
(ii) combination reaction
(iii) redox reaction
(iv) neutralisation reaction
(a) (i) and (iv)
(b) (ii) and (iii)
(c) (i) and (iii)
(d) (iii) and (iv)

Answer: C

Question. Which of the following can be decomposed by the action of light ?
(a) NaCl
(b) KCl
(c) AgCl
(d) CuCl

Answer: C

Question. A student added dilute HCl to a test tube containing zinc granules and made following observations which one is correct?
(a) The zinc surface became dull and black.
(b) A gas evolved which burns with a pop sound.
(c) The solution remained colourless.
(d) The solution becomes green in colour.

Answer: B

Question. The copper coin is dipped in blue coloured copper sulphate solution, the colour obtained after half an hour is
(a) Reddish
(b) Brownish
(c) Colourless
(d) blue colour

Answer: D

Question. When iron nail js kept in blue coloured copper sulphate solution, after a while the colour obtained in the test tube for the solution is
(a) Blue
(b) Brown
(c) Green
(d) Red

Answer: C

Question. Which among the following is (are) double displacement reaction(s)?
(i) Pb + CuCl₂ PbCl₂ +Cu
(ii) Na₂SO₄ + BaCl₂ BaSO₄ + 2NaCl
(iii) C + O₂ CO₂
(iv) CH₄ + 2O₂ CO₂ + 2H₂O
(a) (i) and (iv)
(b) (ii) only
(c) (i) and (ii)
(d) (iii) and (iv)

Answer: B

Question. Which of the following reactions represents a combination reaction?
(a) CaO(s) + H₂O(l) Ca(OH)₂ (aq)
(b) CaCO₃(s) CaO(s) + CO₂(g)
(c) Zn(s) + CuSO₄(aq) ZnSO₄(aq) + Cu(s)
(d) 2FeSO₄(s) Fe₂O₃(s) + SO₂(g) + SO₃(g)

Answer: A

Question. CuO+ H₂→ H₂O+ Cu, reaction is an example of -
(a) redox reaction
(b) synthesis reaction
(c) neutralisation
(d) analysis reaction

Answer: A

Question. White silver chloride in sunlight turns to-
(a) grey
(b) yellow
(c) remain white
(d) red 

Answer: A

Question. When hydrogen sulphide gas is passed through a blue solution of copper sulphate, a black precipitate of coppersulphide is obtained and the sulphuric acid so formed remains in the solution. The reaction is an example of
(a) a combination reaction
(b) a displacement reaction
(c) a decomposition reaction
(d) a double decomposition reaction

Answer: D

Question. Chemically the ‘water gas’ is
(a) H₂O (gaseous)
(b) CO₂ + H₂
(c) CH₄ + H₂O
(d) CO + H₂

Answer: D

Question. What happens when dilute hydrochloric acid is added to iron filings?
(a) Hydrogen gas and iron (II) chloride are produced.
(b) Chlorine gas and ferric hydroxide are produced.
(c) Heat is absorbed, i.e., test tubes becomes cold.
(d) Iron salt and water are produced.

Answer: A

Question. In which of the following equations, the mass is not same on both the sides?
(a) Word equation
(b) Skeletal equation
(c) Balanced equation
(d) Both (a) and (b)

Answer: D

Question. In which of the following the identity of initial substance remains unchanged?
(a) Curdling of milk
(b) Formation of crystals by process of crystallisation
(c) Fermentation of grapes
(d) Digestion of food

Answer: B

Question. Black and white photography uses –
(a) decomposition of silver chloride.
(b) decomposition of silver bromide.
(c) both
(d) none of the options

Answer: B

Question. Which of the following is a decomposition reaction?
(a) 2HgO^Heat→2Hg +O₂
(b) CaCO3^Heat→CaO+ CO₂
(c) 2H2O^Electrolysis→H₂ +O₂
(d) All of these

Answer: D

Question. The equation Cu + xHNO₃ → Cu(NO₃)₂ + yNO₂ + 2H₂O The values of x and y are –
(a) 3 and 5
(b) 8 and 6
(c) 4 and 2
(d) 7 and 1

Answer: C

Question. When copper powder is heated it gets coated with –
(a) black copper oxide
(b) yellow copper oxide
(c) red copper oxide
(d) none of the options

Answer: A

Question. On adding zinc granules to freshly prepared ferrous sulphate solution a student observes that:
(a) a dull brown coating is formed
(b) a black coating is formed
(c) a greyish coating is formed
(d) no coating is formed.

Answer: C

Assertion-Reason Questions

In the following question, a statement of Assertion
(A) is followed by a statement of Reason (R). Answer these questions by selecting appropriate option given below:
(a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
(b) Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A)
(c) Assertion (A) is true but Reason (R) is false.
(d) Assertion (A) is false but Reason (R) is true.

Question. Assertion (A): Quicklime reacts vigorously with water releasing a large amount of heat.
Reason (R): The above chemical reaction is an exothermic reaction.

Answer: A

Question. Assertion (A): Photosynthesis is considered as an endothermic reaction.
Reason (R): Energy gets released in the process of photosynthesis

Answer: C

Question. Assertion (A): A reducing agent is a substance which can either accept electron.
Reason (R): A substance which helps in oxidation is known as reducing agent.

Answer: D

Question. Assertion (A): Pungent smelling gas is produced when sulphur burns in air.
Reason (R): Sulphur trioxide is formed on reaction of sulphur with oxygen.

Answer: C

Question. Assertion (A): Carbon dioxide turns lime water milky.
Reason (R): Carbon dioxide sullies the water.

Answer: C

Fill in the Blanks :

Question. Reactions in which heat is given out along with the products are called ....................... reactions.
Answer: exothermic

Question. When calcium carbonate is heated, it decomposes to give .................. and ................. .
Answer: CaO (s) and CO₂ (g)

Question. Precipitation reactions produce .................... salts.
Answer:  insoluble

Question. Reduction is the ................. of oxygen or gain of hydrogen.
Answer: loss