10 ml of a gaseous hydrocarbon is mixed with excess of oxygen and burnt . The gases are then cooled back . The reduction in volume was 25 ml . When the gases are passed into caustic potash , there is a further reduction in volume of 30 ml . If all volumes are measured under the laboratory conditions , the hydrocarbon is

Explanation

Volume reduction in potash solution = Volume of carbondioxide obtained = 30mL.
10 ml of hydrocarbon `C_(x)H_(y)` gives x x 10 mL of `CO_(2)`
`x=(30)/(10)=3`
Reducation in the volume of the mixture = (volume of `C_(x)H_(y)` + Volume of `O_(2)` required + volume of `O_(2)` excess)
-(volume of `CO_(2)` formed + volume of `O_(2)` excess) = 30mL
`10mL + 10(x+(y)/(4))mL - 10x = 30mL`
`(10y)/(4)=20,y=8`
Formula of hydrocarbon `=C_(3)H_(8)`