Question

The volumes of 4 N HCl and 10 N HCl requiredto make 1 litre of 6 N HCI are

• A. 0.75 litre of 10 N HCI and 0.25 litre of 4 NHCI
• B. 0.25 litre of 4 N HCI and 0.75 litre of 10 NHCI
• C. 0.67 litre of 4 N HCI and 0.33 litre of 10 NHCI
• D. 0.80 litre of 4 N HCI and 0.20 litre of 10 NHCI

Answer 1

Answer: (C)

Let $N_1$ and $V_1$ be normality and volume of $4NHCl$ and $N_2$ be normality and volume of $10NHCl$ respectively.
As volume to make is $1L$ and Normality to make is $6N$,
$<br/>\text{ so }{V}_1+V_2=V<br/>$
As we know $N_1{V}_1+N_2{V}_2=NV$
Calculation to determine $V_1$ and $V_2$ :
Substituting the values in $N_1{V}_1+N_2{V}_2=NV$ equation
$<br/>4\times V_1+10\times \left(1-V_1\right)=6\times 1\left(\text{ As }{V}_2=1-V_1\right)<br/>$
so $V_1=2/3$ and $V_2=1/3$
$V_1=2/3=\mathrm{0..67}$ litre and $V_2=0.33$ litre
Thus, answer is $0.67$ litre of $4NHCl$ and $0.33$ litre of $10NHCl$.