Question

An aromatic hydrocarbon with empirical formula $C_5{H}_4$ on treatment with concentrated $H_{2}S{O}_4$ gave a monosulphonic acid. $0.104g$ of the acid required $10mL$ of $\frac{N}{20}NaOH$ for complete neutralization. The molecular formula of hydrocarbon is

• A. $C_5{H}_4$
• B. $C_{10}{H}_8$
• C. $C_{15}{H}_{12}$
• D. $C_{20}{H}_{16}$
• E. $C_{15}{H}_{20}$

Answer 1

Answer: (C)

Empirical formula $(C_5{H}_4)+H_{2}S{O}_4\to$
Monosulphonic acid
$0.104g$ of acid required $10mL$ of
$\frac{N}{20}NaOH$ for completely neutralization
$\frac{0.104}{n(5\times 12+4\times 1)}=\frac{1}{20}\times 10\times {10}^{-3}$
$n=\frac{104}{32}=3.25\approx 3$
The molecular formula of hydrocarbon will be C is $C_{15}{H}_{12}$ .