Question

$0.4$g of a polybasic acid $H_{n}A$ (all the hydrogens are acidic) requires $0.5$g of NaOH for complete neutralization. The number of replaceable hydrogen atoms in the acid and the molecular weight of 'A' would be:
[Molecular weight of the acid is $96$ g/mole]

• A. 1, 95
• B. 2, 94
• C. 3, 93
• D. 4, 92

Answer 1

The correct option is C 3, 93

Eq. of Acid= Eq. of base

$n\times \frac{0.4}{96}=\frac{0.5}{40}$
$n=\frac{1}{80}\times \frac{96}{0.4}=\frac{96}{32}=3$
$\therefore$ Atomic weight of A$=96-3=93$

Hence, option C is correct.