One litre of ${\mathrm{CO}}_2$ is passed over hot coke. The volume becomes 1.4 lit. The resultant mixture contains

${\mathrm{C}}_{\left(\mathrm{s}\right)}+{\mathrm{CO}}_{2\left(\mathrm{g}\right)}\to 2{\mathrm{CO}}_{\left(\mathrm{g}\right)}$

1mol         2mol            

(1 − x)         2x

Total volume (1 − x) + 2x = 1 + x= 1.4

x=0.4 Lt

Given volume of ${\mathrm{CO}}_2=1 \mathrm{Lt}$

Volume of ${\mathrm{CO}}_2$ remain = 1 − 0.4 = 0.6 Lt

Volume CO formed = 2 × 0.4 = 0.8 Lt .