Question

If 1.4 g of calcium oxide is formed by the complete decomposition of calcium carbonate, then the amount of calcium carbonate taken and the amount of carbon dioxide formed will be respectively :

विकल्प

• 2.2 g and 1.1 g

• 1.1 g and 2.5 g

• 2.5 g and 1.1 g

• 5.0 g and 1.1 g

Answer 1

2.5 gm and 1.1 gm

Molecular mass of CaCO₃: 40 + 12 + (16 × 3) = 100g
Molecular mass of CaO: 40 + 16 = 56g
Molecular mass of CO₂: 12 + (16 × 2) = 44g
Reaction for the decomposition of calcium carbonate:

CaCo₃ → CaO + CO₂

100g      56g    44g
  X          1.4g     Y

56 g of CaO is obtained when 100g of CaCO₃ is burnt.
Therefore, to get 1.4g of CaO, the amount of CaCO₃ to be burnt will be

`(100xx1.4)/56 =2.5g`

For CO₂,
100g of CaCO₃ yields 44g of CO₂
Therefore, 2.5g of CaCO₃ will yield;

`44xx2.5/100 = 1.1 "g"`