Anhydrous sodium sulphate (14.2 g) is heated with excess carbon: $Na X_{2} SO X_{4} + 4 C Na X_{2} S + 4 CO$ . The carbon monoxide produced is then burnt completely in air to carbon dioxide. Using Na 23, S 32, O 16 and 22.4 L per mol at STP, the volume of $CO X_{2}$ formed is

Answer: B

Molar mass of

Na X_{2} SO X_{4}

is 142 g/mol, so 14.2 g is 0.100 mol, which gives

4 \times 0.100 = 0.400

mol CO.

2 CO + O X_{2} 2 CO X_{2}

gives 0.400 mol

CO X_{2}

, whose volume at STP is

0.400 \times 22.4 = 8.96