Two solids X and Y dissociate into gaseous products at a certain temperature as follows:
i. `X(s) hArr A(g)+C(g)` and
ii. `Y(s) hArr B(g)+C(g)`
At a given temperature, pressure over excess solid 'X' is `40` mm of Hg and total pressure over solid 'Y(s)' is `60` mm of Hg.
Now, answer the following questions:
The ratio of moles of A and B in the vapour state over a mixture of solids X and Y, is:

Options

A. `2:3`
B. `2:5`
C. `4:9`
D. `1:1`

Answer

C

Explanation

In mixture, solid X and Y dissociate simultaneous,
`{:(X(s),hArr,A(g),+,C(g)),(,,p_(1),,(p_(1)+p_(2))),(Y(s),hArr,B(s),+,C(s)),(,,p_(2),,(p_(2)+p_(1))):}`
`:. K_(p_(1))/K_(p_(2))=p_(1)/p_(2)=4/9`
Hence, (c) is the correct answer.