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

Explanation

Let a cm from `HCI` end white fumes of `NH_(4)CI` are noticed
From Graham's law
`(r_(HCI))/(r_(NH_(3))) = sqrt(M_(NH_(3))/M_(HCI))`
or `(a)/(t) xx (t)/((200 -a)) = sqrt((17)/(36.5))`
(time of diffusion in tube for both is same)
`:. a =81.1 cm` from `HCI` end
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