A sample of NH4HS(s) is placed in a 2.57 −L flask containing 0.140 mol NH3(g).

Question

NH4HS(s)⇌NH3(g)+H2S(g)KP=0.108at25∘C
What will be the total gas pressure when equilibrium is established at 25∘C?

any idea on how to solve it like an outline?
Thanks

Answer 1

Use PV = nRT and solve for pNH3 initially. Substitute pNH3 from this calculation into the below.
pNH3 is approx 1.5 but you need a more accurate number.
...........NH4HS ⇌ NH3 + H2S
I.........solid....1.5....0
C.........solid.....+x....x
E.........solid....1.3+x...x

Substitute the E line into the Kp expression and solve for x, then evaluate 1.5(or whatever that number is) +x
Ptotal = pNH3 + pH2S