set 1 MCQ Questions & Answers Detailed Explanation

Question : 1

Which one is a decomposition reaction ?

a) 2H₂O $⟶ ↖ {Electrolysis}$ 2H₂ + O₂

b) 2HgO $⟶ ↖ {heat}$ 2Hg + O₂

c) CaCO₃ $⟶ ↖ {heat}$ CaO + CO₂

d) All the above reactions are decomposition reaction

Question : 2

$Na_2S_2O_3$ represent the compound

a) sodium thiosulphate

b) sodium sulphate

c) sodium sulphite

d) None of these

Question : 3

The chromate and dicharomate ions are respectively

a) CrO^-₄ and CrO^-₅

b) CrO^2-₄ and Cr₂O^2-₇

c) Cr₂O^2-₇and CrO_4-

d) CrO^2-₄ and Cr₂O^2-₅

Question : 4

Valency of an atom or radicals is

a) its combining capacity

b) ionisation energy

c) electron affinity of atom

d) size of atom

Question : 5

Which of the following reaction is endothermic?

a) CH₄ + 2O₂ ⟶ CO₂ + 2H₂O

b) C + O₂ ⟶ CO₂

c) CaCO₃ ⟶ CaO + CO₂

d) CaO + H₂ O ⟶ Ca(OH)₂

Question : 6

Which one is a combination reaction ?

a) Ca(OH)₂ + Na₂CO₃ ⟶ 2NaOH + CaCO₃ ↓

b) Formation of a mixture of carbon monoxide and hydrogen. When steam is passed over red hot iron.

c) Reaction of water with sodium metal to form sodium hydroxide and hydrogen.

d) Preparation of stannic chloride (Tin (iv) chloride) by passing chlorine gas into molten tin (Sn).