Ethene undergoes incomplete combustion to form carbon dioxide, carbon monoxide and water vapour. If the ratio of carbon dioxide to carbon monoxide formed is 9:1 when x cm^3 of ethene is burnt, what is the volume of oxygen gas consumed in the reaction?

1 Answer
May 29, 2017

Ethene undergoes incomplete combustion to form carbon dioxide, carbon monoxide and water vapour. The balanced equation of this incomplete combustion reaction is as follows.

C_2H_4(g)+5/2O_2(g)->CO_2(g)+CO(g)+2H_2O(g)

But as per question the ratio of volumes of CO_2(g):CO(g) produced is 9:1. So this also represents the mole ratio of
CO_2(g):CO(g) produced.

Hence adjusting this ratio balanced equation may be written as follows
10C_2H_4(g)+39/2O_2(g)->9CO_2(g)+CO(g)+20H_2O(g)

Here we see 10cm^3 C_2H_4(g) will require 39/2=19.5cm^3"" ""O_2(g)

So to burn xcm^3 ethene the required volume of oxygen will be 19.5/10xx xcm^3=1.95xcm^3