Question

A solution containing $3.00g$ of a monobasic organic acid was just neutralised by $40mL$ of $0.5NNaOH$ solution. Calculate the molecular weight of the acid.

Answer 1

$HA+NaOH\to NaA+H_{2}O$

$40mL$

$0.5N$

Mole of $HA=$ mole of $NaOH=40\times {10}^{-3}\times \frac{5}{10}\times 1$

$\frac{3}{Mol.wt.ofacid}=20\times {10}^{-3}$

$\therefore$ Mol. wt. of acid $\frac{3\times {10}^3}{20}=\frac{300}{2}=150g$