Question

Through the two ends of a glass tube of length $200cm$ hydrogen chloride and ammonia gases are allowed to enter. At what distance ammonium chloride will first appear?

Answer 1

Let X be the length from the HCl end, and therefore, (2-x) from the other end.

For X length, rate of diffusion is :

$\frac{dx}{dt}=PA/\left(\sqrt{36.5T}\right)$

$d(2-x)/dt=PA/\left(\sqrt{17T}\right)$

Dividing both we get;

$X/(2-x)=\sqrt{\frac{36.5}{17}}$

$X=2/2.466=0.81mor81cm$

Hence, 81cm is the answer.