general concepts of chemistry - Category wise Question and Answer Practice Test with Solutions

Question : 11

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 : 12

$Na_2S_2O_3$ represent the compound

a) sodium thiosulphate

b) sodium sulphate

c) sodium sulphite

d) None of these

Question : 13

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 : 14

A redox reaction is one in which -

a) an acid is neutralised by the base

b) both the substance are reduced

c) both the substance are oxidised

d) one substance is oxidised while the other is reduced

Question : 15

Slow eating away of iron articles in the presence of moist air is called

a) rusting

b) galvanisation

c) crystallisation

d) neutralisation