set 1 MCQ Questions & Answers Detailed Explanation

Question : 1

Which of the following statements is not correct?

a) A chemical equations tells us about the atom or molecules of the reactants and products involved in a reaction

b) A chemical equations tells us about the substances involved in a reaction.

c) A chemical equations informs us about the symbols and formula of substances involved in a reaction

d) All are correct

Question : 2

In the following equations : NaCO₃ + xHCL ⟶ 2NaCl + CO₂ + H₂O, the value x is

a) 3

b) 1

c) 2

d) 4

Question : 3

The total number of atoms represented by the compound CuSO₄ .5H₂O is

a) 5

b) 27

c) 21

d) 8

Question : 4

When hydrogen sulphide gas is passed through a blue solution of copper sulphate, a black precipitate of copper sulphide is formed. This is an example of

a) decomposition reaction

b) combination reaction

c) displacement reaction

d) double decomposition reaction

Question : 5

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

a) rusting

b) galvanisation

c) crystallisation

d) neutralisation

Question : 6

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