Question #343ff

1 Answer
Sep 27, 2016

Let the molecular formula of HC be CxHy

And the balanced equation of the combustion reaction of the HC in oxygen is

CxHy+(x+y4)O2(g)xCO2(g)+y2H2O(l)

So by this equation the stochiometric ratio of CO2 and H2O produced on combustion is
=xmoly2mol=44xg182yg=44x9y
Where 44gmol is the molar mass of CO2and18gmol is the molar mass of H2O

But by the given data this ratio is

321mg64mg=321645

So equating these two we get

44x9y=5

xy=454411

Since the ratio of number of atoms C and H in the HC molecule is 1:1 then we can easily say the Empirical formula of HC is CH