9 " mL of " a mixture of methane and ethylene was exploded with 30 mL (excess) of oxygen. After cooling, the volume was 21.0 mL. Further treatment with caustic potash solution reduced the volume to 7.0 mL. Determine the composition of the mixture.

Explanation

Let the volume of `CH_4=xmL`
Volume of `(CH_2=CH_2)=(9-x)mL`
(a). `CH_4(g)+2O_2(g)toCO_2(g)+2H_2O(l)`
(b). `CH_2=CH_2(g)+3O_2(g)to2CO_2(g)+H_2O(l)`
Volume of `CO_2` absorbed by `KOH=21-7=14mL`
`thereforex+2(9-x)=4mL`
`thereforex=4mL`
Volume of `CH_4=4mL`
Volume of `CH_2=CH_2=9-4=5mL`