Question

$1\text{L}$ of a $\frac{N}{2}HCl$ solution is heated in a beaker. It was observed that when the volume of the solution was reduced to $600\text{mL}$, $3.25\text{g}$ of $HCl$ is lost. Calculate the normality of the new solution.

• A. $1.70\text{N}$
• B. $0.685\text{N}$
• C. $0.342\text{N}$
• D. $0.171\text{N}$

Answer 1

The correct option is B $0.685\text{N}$

$\text{Normality}=\frac{\text{number of gram equivalents}}{\text{total volume of the solution in L}}$
Number of gram equivalents of $HCl$ = 0.5
Mass of $HCl$ in solution $=0.5\times 36.5=18.25\text{g}$
Mass of $HCl$ remaining $=18.25–3.25=15\text{g}$
Number of gram equivalents of $HCl$ $=\frac{15}{36.5}$
New volume $=0.6\text{L}$
New normality $\frac{15/36.5}{0.6}=0.685\text{N}$