10.0 ml mixture of methane and ethylene was exploded with 30ml (excess) of oxygen. After cooling the volume was 21.0 ml. On treatement with KOH solution the volume was reduced to 7.0 ml. The amounts of methane and ethylene in the mixture respectively are

Let the vol. of CH4  be = a ml         Vol. of  C2H4=(10−a)  ml Equation for combustion of CH4  and C2H2  CH4+2O2    →   CO2+2H2O    (liquid) a  ml     2a ml          a ml     negligible volumeC2H4     +     3O2   →    2CO2  +    2H2O (10 – a) ml  3(10 – a)ml   2(10 – a) ml negligibleVol. of CO2  produced + O2  left = 21 mlVol. of CO2  produced =21−7=14 ml CO2  produced isa+2(10−a) = 14 ∴     a=6 ∴    Vol.  of CH4=6 ml   and  vol.  of  C2H4=4 ml