Question

A straight glass tube has inlet $X$ and $Y$ at the two ends. The length of the tube is $200cm$.$HCl$ gas through inlet $X$ and ${NH}_3$ gas through inlet $Y$ are allowed to enter the tube at the same tube. White fumes first appears at a point $P$ inside the tube. Find the distance of $P$ from $X$.

Answer 1

White fumes occur where ${NH}_3$ meets $HCl$

rate $\alpha \frac{1}{\sqrt{M.W}}$ (Graham's law of diffusion)

also known that more rate more distance covered. So rate $\alpha$ distance.

$\frac{d_{{NH}_3}}{d_{HCl}}=\frac{\sqrt{HCl}}{\sqrt{{NH}_3}}$

$\frac{200-x}{x}=\frac{\sqrt{365}}{\sqrt{17}}$

$x=81.22cm$

$81.22cm$ from inlet $X$.