Question

$1\text{L}$ of a solution contains $18.9\text{g}$ of $HN{O}_3$ and $1\text{L}$ of another solution contains $3.2\text{g}$ of $NaOH$. In what volume ratio must the solutions be mixed to obtain a neutral solution?

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

Answer 1

The correct option is B $4:15$

Let $V_{HN{O}_3}$ be the volume of the $HN{O}_3$ solution and $V_{NaOH}$ be the volume of the $NaOH$ solution.
Normality of $HN{O}_3=\frac{18.9/63}{1}=0.30\text{N}$
Normality of $NaOH=\frac{3.2/40}{1}=0.08\text{N}$
For a neutral solution, Equivalents of $HN{O}_3$ = Equivalents of $NaOH$
$0.30\times V_{HN{O}_3}=0.08\times V_{NaOH}$
$\frac{V_{HN{O}_3}}{V_{NaOH}}=\frac{4}{15}$