Question

When a gaseous olefinic hydrocarbon is burnt
completely in excess of O2, a contraction in
volume equal to double to the volume of
hydrocarbon is noticed then hydrocarbon will be
(1) C2H2
(2) C2H4
(3) C2H6
(4) C3H8
​

Answer 1

Answer:

When a gaseous olefinic hydrocarbon is burnt completely in excess of O2, a contraction in volume equal to double to the volume of hydrocarbon is noticed then hydrocarbon will be C2H4.

Explanation:

Suppose the gaseous olifenic hydrocarbon formula is CxHy +O2 = xCO2 + y/2H2O

Volume contraction = hydrocarbon volume + O2 volume – CO2 volume

So, contraction volume = 4 + y/4

As per the question 4 + y/4 = 2 volume of hydrocarbon  

So, y=4 The given hydrocarbon in the gaseous form.

Therefore contraction of volume of CO2 = Contraction volume of H2O so x=y/2

X = 2 so the resultant hydrocarbon will be C2H4.

Answer 2

When a gaseous olefinic hydrocarbon is burnt

completely in excess of O2, a contraction in

volume equal to double to the volume of

hydrocarbon is noticed then hydrocarbon will be

(1) C2H2

(2) C2H4✔

(3) C2H6

(4) C3H8