Question

An aqueous solution of $6.3$ g oxalic acid dihydrate is made up to $250$ mL. The volume of $0.1\text{N}$ $\text{NaOH}$ required to completely neutralize $10$ mL of this solution is:

• A. $40$ mL
• B. $20$ mL
• C. $10$ mL
• D. $4$ mL

Answer 1

The correct option is A $40$ mL

Hydrated oxalic acid, $(COOH{)}_2.2H_{2}O$ has a molecular weight of $126$ g/mol.

Equivalent weight $=\frac{M}{2}=63$

For complete neutralisation, both require the same number of equivalents.

$N_1{V}_1=N_2{V}_2$

Meq. of oxalic acid $=$ Meq. of NaOH

Oxalic acid is a dibasic acid as it can release two H+

Molarity$=\frac{(6.3\times 1000)}{(126\times 250)}=0.2M$

$\Rightarrow$ normality $=0.2\times 2=0.4N$

For req volume of NaOH

$0.4\times 10=0.1\times V_2$

$\Rightarrow V_2=40$ mL

Hence, the correct option is $A$