Question

A hydrocarbon contains 82.8%of carbon . Find it's molecular formula if vapor density is 29

Answer 1

1. Vapour Density = Molar mass of gasMolar mass of H229 =M2Molar mass of compound = 58

2. The gas contains 82.8% of C and 17.2% of H.
   
 Atomic mass of C = 12
Atomic mass of H = 2

So, Number of moles of C = 82.812=6.9
     Number of moles of H = 17.21=17.2
3. Simplest ratio :
   C = 6.96.9=1
  H = 17.26.9=2.4 ≈2
So, Molecular mass is C4H10.