Question

The stopcocks of the bulbs $X$ (containing $N{H}_3$) and $Y$ (containing $HCl$), both under identical conditions, are opened simultaneously. White fumes of $N{H}_{4}Cl$, are formed at point $B$. If $AB=36.5cm$, then $BC$ is approximately :

• A. 18.0 $cm$
• B. 25.0 $cm$
• C. 20.0 $cm$
• D. 36.5 $cm$

Answer 1

The correct option is B 25.0 $cm$

$\frac{r_{HCl}}{r_{NH3}}=\frac{{\mu }_{HCl}}{{\mu }_{NH3}}=\sqrt{\frac{17}{36.5}}=0.682$

$\therefore {\mu }_{HCl}=0.682\times {\mu }_{NH3}$

$\therefore$ $\text{Average distance travelled by}$ $HCl=0.682\times$ $\text{Average distance travelled by}$ $N{H}_3$

$0.682\times 36.5=24.9\approx 25.0cm$