Derive the formula of a hydrocarbon with a mass fraction of elements carbon-92.31%

Derive the formula of a hydrocarbon with a mass fraction of elements carbon-92.31%, hydrogen-7.69% and a vapor density of hydrogen 39. Give it a name.

Let’s denote the unknown hydrocarbon as CxHy.
The molar mass of a given substance in terms of hydrogen is.
Mr (CxHy) = D (H2) • Mr (H2) = 39 • 2 = 78.
Let’s compose the ratio of the percentage to molar mass.
CxHy = 92.31 / 12: 7.69 / 1 = 7.69: 7.69.
CxHy = 1: 1.
Molar mass of the resulting substance.
Mr (CH) = 12 + 1 = 13.
Which does not correspond to the true molar mass. Let’s find the hydrocarbon indices according to the formula.
CxHy = Mr (source) / Mr (CH) = 78/13 = 6.
The found substance C6H6 is benzene.