Hydrogen chrolide gas is sent into a 100 metre tube from one end 'A and ammonia gas from the other end 'B', under similar conditions. At what distant from 'A' will be the two gases meet.

Explanation

The two gases HCl and `NH_3` diffuse into the pipe from the ends A and B respectively to meet at a point O as indicated by formation of white ring of `NH_4 Cl`. If the distance AO is x meters, the distance OB will be (100 - x) metres.
According to Graham.s law of diffusion. Ration of rates of diffusion of HCl and `NH_3` gas is given by
` =( 735 m m xx 101 .3 K Pa )/( 1760 m m ) = 98 k Pa `
It means that the two gases meet at the point o such that the ratio of the distances from the end A to O and B to O is 0.68: 1.00
` therefore ( 0. 68)/(1) = (x) /( (100-x))`
`or 0.68 (100 -- x)= x or 68 -0.68 x = x
or 68 = x + 0.68 x or 68 = x (1 + 0.68)= 1.68 x `
` x= (68)/(1.68) = 40 . 48 ` metres
hence the two gases meet at a distance of 40.48 metres from the end .A..