Question

Number of hydrogen atoms per molecule of a hydrocarbon A having $85.8\%$ carbon is_____ (Given: Molar mass of $A=84gmo{l}^{-1}$ )

Answer 1

Answer: 12

Element	Percentage	Mole	Mole ratio
C	85.8	$\frac{85.8}{12}=7.15$	1
H	14.2	$\frac{14.2}{1}=14.2$	2

Empirical formula $\left(C{H}_2\right)$
$14\times n=84$
$n=6$
$\therefore$ Molecular formula $C_6{H}_{12}$