Two solid `X` and `Y` dissociate into gaseous products at a certain temperature as followas:
`X(s)hArrA(g)+C(g)` , and `Y(s)hArrB(g)+C(g)`
At a given temperature, the pressure over excess solid `X` is `40 mm` and total pressure over solid `Y` is `80 mm`. Calculate
a. The value of `K_(p)` for two reactions.
b. The ratio of moles of A and B in the vapour state over a mixture of `X` and `Y`.
c. The total pressure of gases over a mixture of `X` and `Y`.

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.