Question

Question #343ff

Answer 1

Let the molecular formula of HC be `C_xH_y`

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

`C_xH_y+(x+y/4)O_2(g)->xCO_2(g)+y/2H_2O(l)`

So by this equation the stochiometric ratio of `CO_2` and `H_2O` produced on combustion is
`=(xmol)/(y/2 mol)=(44xg)/(18/2yg)=(44x)/(9y)`
`"Where " 44g/"mol"" is the molar mass of "CO_2 and 18g/"mol" " is the molar mass of "H_2O`

But by the given data this ratio is

`(321mg)/(64mg)=321/64~~5`

So equating these two we get

`(44x)/(9y)=5`

`=>x/y=45/44~~1/1`

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 `color(red)(CH)`