Chapter 1
Chemical Reactions and Equations
MCQs
Q 1.: A student performs an experiment to form aluminium chloride from aluminium and chlorine. Which options give the chemical equation of the reaction?
(A) Al + Cl2 → AlCl2
(B) 2Al + 3Cl2 → 2AlCl3
(C) 2Al + Cl2 → 2AlCl
(D) 3Al + 3Cl2 → 3AlCl3
Option – B
Q 2.: Give the ratio in which hydrogen and oxygen are present in water by mass.
(A) 1:2
(B) 1:1
(C) 1:8
(D) 2:1
Option – C
Q 3.: Give the ratio in which hydrogen and oxygen are present in water by volume.
(A) 1:4
(B) 1:1
(C) 1:8
(D) 2:1
Option – D
Q 4.: Sodium and chlorine are reacted and as a result, sodium chloride is formed which is also called table salt. What option gives the reactants and products of the reaction?
(A) Reactants – sodium; products – chlorine
(B) Reactants – tables salt; products – sodium and chlorine
(C) Reactants – sodium and table salt; products – chlorine
(D) Reactants – sodium and chlorine; products – sodium chloride
Option – D
Q 5.: The chemical formula of magnesium oxide is?
(A) Mg2O
(B) MgO
(C) MgO2
(D) Mg(OH)2
Option – B
Q 6.: In the reaction, xKClO_{3} \overset{Heat}{\rightarrow} yKCl + zO_{2} the values of x,y and z are
(A) 1,2,3
(B) 2,1,3
(C) 2,2,3
(D) 2,2,1
Option – C
Q 7.: Which of the following involves a chemical reaction?
(A) Storing of oxygen gas under pressure in a gas cylinder
(B) Liquefication of air
(C) Keeping petrol in a china dish in open
(D) Heating copper wire in the presence of air at high temperature
Option – D
Q 8.: The following reaction is used in laboratory for the preparation of oxygen gas: 2KClO_{3}(s)\xrightarrow[Catalyst]{Heat}2KCl(s) + 3O_{2}(g)
Which one of the following statements satisfies this reaction?
(A) It is a decomposition reaction and endothermic in nature.
(B) It is a combination reaction.
(C) It is a decomposition reaction and exothermic in nature
(D) It is photochemical decomposition reaction and exothermic in nature
Option – A
Q 9.: 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) 8:1
Option – B
Q 10.: The reaction, Fe_{2}O_{3}(s)+2Al(s)\rightarrow Al_{2}O_{3}(s)+2Fe(s) is an example of
(A) Displacement reaction
(B) Decomposition reaction
(C) Combination reaction
(D) Double displacement
Option – A
Q 11.: To prevent the chips from going rancid, the bags of chips are flushed with
(A) Hydrogen
(B) Nitrogen
(C) Oxygen
(D) Carbon dioxide
Option – B
Q 12.: Which of the following are exothermic process?
(A) Reaction of quicklime with water
(B) Dilution of sulphuric acid
(C) Evaporation of water and Sublimation of camphor
(D) (a) and (b)
Option – D
Q 13.: Decomposition of a substance by an electric current is called
(A) Electrical synthesis
(B) Electrolysis
(C) Electrophoresis
(D) Electroosmosis
Option – B