1 litre mixture of CO and CO2 is taken. This is passed through a tube containing red hot charcoal. The volume now becomes 1.6 litre. The volumes are measured under the same conditions. Find the composition of mixture by volume.

We have
initial volume of CO+CO2 =1 lt
final volume of the mixture =1.6lt
this final volume has increased due to the more CO formed
C+CO2 ---2CO
Let the initial volume of CO2 be xlt,volume of CO=1-x lt
initial volume of CO2=x
final volume of CO=2x
therefore final volume of 1-x+2x=1+x
1+x=1.6
x=.6lt
volume of CO2=.6lt
volume of CO=.4lt
percentage of CO2=60%
percentage of CO=40%