Calculate and give the empirical formula of hydrocarbon?

Question

An unsaturated hydrocarbon known to be either ethene or ethyne reacts with excess bromine to give a substance containing 85% bromine and 12.8% carbon by mass, the remainder being hydrogen.

Answer 1

Both ethene and etyne have two carbon atoms

Thus x*12.8/100 = 24

So, x = 187.5

Number of Bromine atoms = 187.5*100/(85*80) is approximately 2

So, it is ethene having the empirical formula CH2.