Question

How much quick lime can be obtained from 25 gm of CaCO₃?

(a) 28 g

(b) 14 g

(c) 56 g

(d) none

Answer 1

Correct option is (b) 14 g

The reaction is CaCO₃​ ⇌ CaO + CO₂​.

One mole of calcium carbonate on decomposition gives one mole of calcium oxide.

The molecular weight of calcium carbonate and calcium oxide are 100 g/mol and 56 g/mol respectively.

The decomposition of 100 g of calcium carbonate will give 56 g of calcium oxide.

Hence, the decomposition of 25 g of calcium carbonate will give 14 g of calcium oxide (quicklime).