Question

$20mL$ of $0.1M{H}_{3}B{O}_3$ solution on complete neutralisation requires $xmL$ of $0.05MNaOH$ solution. The value of $x$ will be:

• A. $20mL$
• B. $40mL$
• C. $120mL$
• D. $80mL$

Answer 1

The correct option is B $40mL$

Boric acid is monobasic acid.
$H_{3}B{O}_3+NaOH\to Na\left[B\right(OH{)}_4]$
$\frac{M_1{V}_1}{n_1}=\frac{M_2{V}_2}{n_2}$
$\frac{0.1\times 20}{1}=\frac{0.05\times x}{1}$
$x=40mL$.