set 3 MCQ Questions & Answers Detailed Explanation

Question : 1

The formation of SO₂ and SO₃ explain

a) the law of multiple proportions

b) the law of definite properties

c) the law of conservation of mass

d) Boyle’s law

Question : 2

The number of neutrons in ₇Al²⁷ is

a) 14

b) 27

c) 40

d) 13

Question : 3

Which of the following isotopes of carbon is/are used in carbon dating?

a) ₆ C¹⁴ only

b) ₆ C¹³ only

c) ₆ C¹² only

d) ₆ C¹² and ₆ C¹⁴

Question : 4

Dalton's atomic theory successfully explained

1. Law of conservation of mass
2. Law of constant composition
3. Law of radioactivity
4. Law of multiple proportions

a) (i), (iii) and (iv)

b) (ii), (iii) and (iv)

c) (i), (ii) and (iii)

d) (i), (ii) and (iv)

Question : 5

What is the weight of one atom of Hydrogen in grams?

a) 6.62 × 10^–24

b) 1.66 × 10^–24

c) 6.023 × 10^–23

d) None of these

Question : 6

In a chemical change the total weight of the reacting substances compared to total weight of products is

a) always less

b) always more

c) never the same

d) always the same