Two solids components A and B dissociate into gaseous products at 20°C as
i) A(s) → A'(g) + H2S(g)
ii) B(s) → B'(g) + H2S(g)
At 20°C pressure over the excess solid A is 50 mm Hg and that over excess solid B is 68 mm Hg.
find
a) The dissociation constants of A and B
b) the ratio of the number of moles of A' and B' in the vapor phase over a mixture of solids A and B
c) The total pressure of gas over the solid mixture.
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1 Answers
71The dissociation constant is the Equilibrium constant I presume. Now
a)
Kp = P2 . P2 = P24 , Where P is the total pressure as given and since the molefraction of each component is 1/2.
This expression should be written for both A and B, therefrom you'll get KpA and KpB
When both are mixed,
A(s) → A'(g) + H2S(g)
x x+y
B(s) → B'(g) + H2S(g)
y x+y
Again write KPA = PT x2x+y . PT (x+y)2x+y and similarly KpB , Now you know these quantities and hence you can solve them for x and y (since there are two relations.)
And Subsequently you'll get PT = Total Pressure.
