Question

The empirical formula weight of a compound containing carbon and hydrogen is $13$. The molecule of the compound is $39$ times heavier than a molecule of hydrogen. The molecular formula of the compound is:

• A. $CH$
• B. $C_3{H}_3$
• C. $C_{13}{H}_{13}$
• D. $C_6{H}_6$

Answer 1

The correct option is D $C_6{H}_6$

The empirical formula weight of a compound containing carbon and hydrogen is $=13$

The atomic weight of $C=12$ and $H=1$

$\Rightarrow$ The empirical formula of compound $=CH$

The weight of molecule of the compound is $=39\times weightof\left[H_2\right]$

$\Rightarrow$ Weight $=39\times 2=78g/mol$

Number of compound $CH$ in molecule $=\frac{78}{13}=6$

The molecular formula of compound$=C_6{H}_6$