An aqueous solution of `6.3 g` oxalic acid dihydrate is made up to `250 mL`. The volume of `0.1 N NaOH` required to completely neutralise `10 mL` of this solution is

Options

A. (a)40 mL
B. (b)20 mL
C. (c )10 mL
D. (d)4 mL

Answer

A

Explanation

Strength of oxlic acid `(underset(COOH)overset(COOH)|2H_(2)O)=6.3 g//250 mL` or
strength of oxalic acid`=6.3xx4 g//L=25.2 g//L`
Normality of oxalic acid and `solution=("Strength un g"//L)/("Equivalnet. Wt.")`
`=25.2/63N=0.4N`
Suppose, x mL volume of `0.1 N NaOH` is required to complete neutralization of `10 mL` of this solution.
So, M. eq. of `NaOH=0.1xx(x)` by, `NxxI in mL`
M.eq. of oxalic acid`=0.4xx10`
On complete neutralization, one M. eq. of acid is neutralized with one M. eq. of base.
So, M. eq. of `NaOH=M`. eq. of oxalic acid
`:. 0.1xx(x)=0.4xx10`
`x=(0.4xx10)/0.1=40 mL`