We know that the relationship between Kc and Kp is Kp = Kc (RT)Δn
What would be the value of ∆n for the reaction
NH4 Cl (s) ⇋ NH3 (g) + HCl (g)
In the equation Kp = Kc (RT) Δn,∆n equals to the difference b/w the number of moles of gaseous products and gaseous reactants where, Kp and Kc are the Equilibrium constants at constant pressure and temperature respectively.
For the reaction NH4 Cl (s) ⇋ NH3 (g) + HCl (g)
The no. of moles of reactant is 1 ( 1 molecule of ammonium chloride involved) and the no. of moles of reactant is 2 ( ammonia and HCl )
Then ,∆n = (2 – 1 ) = 1.