Question #a83c1

1 Answer
Aug 16, 2016

The reaction was initiated by volimetric ratio of Hydrigen and Nitrogen as 3:1 and at equilibrium the ratio remained more or less same 36%:13%~~3:1 (Within experimental error.)
So the volume of NH_3 in the equilibrium mixture may be taken as (100-36-13)%=51%

If the pressure of the reaction mixture at equilibrium be P atm then the partial pressures of the constituents of the reaction mixture will be as follows.

Partial presssure of Hydrogen
p_(H_2)=36%ofP=0.36P" atm"

Partial presssure of Nitrogen
p_(N_2)=13%ofP=0.13P" atm"

Partial presssure of Ammonia
p_(NH_3)=51%ofP=0.51P" atm"

The equation of the gaseous reaction:

3H_2(g)+N_2(g)rightleftharpoons2NH_3(g)

Now the equlibrium constant of the gaseous reaction in respect of pressure is given by

K_p=(p_(NH_3))^2/(p_(N_2)xx(p_(H_2))^3)

=>K_p=(0.51P)^2/(0.13Pxx(0.36P)^3)" atm"^-2

~~42.88P^-2" atm"^-2

If the value of P is known then K_p can be calculated out.