Derive the molecular formula for a hydrocarbon containing 92.3% carbon. The relative density of the vapors

Derive the molecular formula for a hydrocarbon containing 92.3% carbon. The relative density of the vapors of this substance in terms of hydrogen is 13. Give the name to the substance.

w (H) = 100% -92.3% = 7.7%
Let m (connection) = 100 g
then
m (H) = 7.7 g n (H) = 7.7 \ 1 = 7.7 mol
m (C) = 92.3 g n (C) = 92.3 \ 12 = 7.7 mol
n (H): n (C) = 7.7: 7.7 = 1: 1
The simplest formula is CH (13 g / mol)
M = 13 * 2 = 26 g \ mol
26 \ 13 = 2
We multiply by 2 the number of carbon and hydrogen atoms in the simplest formula, we get: C2H2
Answer: C2H2 acetylene