chemistry
posted by selvi .
On passing 2 litres of a mixture of CO and CO2 over red hot charcoal, the volume becomes 2.5 litres. The volume fraction of Co in the mixture is

So, some of the CO2 became CO.
CO2+ C> 2CO
If you assume all the CO2 was converted, then the the added volume of .5 liters equals the new CO, minus the original CO2
2.5litersCO= xlitersCOoriainal+ 2(2x)liters CO new.
2.5=x+42x if my algebra is right, so
1.5=x
or the original amount of CO was 1.5, or 3/4 of the original mixture was CO.