Question

One litre of a solution contains $18.9$g of $HN{O}_3$ and one litre of another solution contains $3.2$g of $NaOH$. In what volume ratio must these solutions be mixed to obtain a neutral solution?

• A. $3:8$
• B. $8:3$
• C. $15:4$
• D. $4:15$

Answer 1

Answer: (D)

$4:15$

We know,

For one litre solution of the mixture the equivalents will be equal.

Equivalent of $HN{O}_3$=Equivalent of $NaOH$

$\frac{18.9}{63}\times 1=\frac{3.2}{40}\times 1$
$⟹3:\frac{4}{5}$
$⟹15:4$ is the rati of equivalent

For neutral solution both equivalents are equal,

Equivalent of $HN{O}_3$=Equivalent of $NaOH$

$15\times V_{HN{O}_3}=4\times V_{NaOH}$

$⟹\frac{V_{HN{O}_3}}{V_{NaOH}}=\frac{4}{15}$