Question

When 10 g of 90% pure limestone is heated completely, the volume (in litres) of carbon dioxide liberated at STP is

(a) 22.4

(b) 2.24

(c) 20.16

(d) 2.016

Answer 1

Correct option is (d) 2.016

Amount of pure limestone (CaCO₃) is 10 g of 90% sample = \(\frac{90}{100} \times 10 \) = 9g

Molecular mass of CaCO₃ = 100

Thus 100 g of limestone gives 22.4 litres of CO₂ at STP

9 g of limestone will give \(\frac{22.4}{100}\) x 9 = 2.016 lit