Hello!!!!

Hope you are doing great!!!

If you want to find Kc, then the procedure is as follows:::;

As per the question reaction is as follows:

N2+3H2  gives rise to 2NH3

Kp=Kc*(RT)^Δ n

Δn= -2  (As per the given reaction)

Given Kp=6.8*10^5

R=8.314 atm.lit/mol.k

T=298 Kelvin

6.8*10^5 = Kc/(RT)^2

Kc=(6.8*10^5) x (RT)^ 2

Kc=(6.8*10^5) x (8.318 * 298 )^2

On Solving,We get Kc=4.5*10^12

Hope it helps!!!!