A sample of solid ammonium chloride was placed in an evacuated container and then heated so that is decomposed to ammonia gas and hydrogen chloride gas. After heating, the total pressure in the container was found to be 6 atm. Calculate Kp (equilibrium constant based on partial pressures) at this temperature for the decomposition reaction
NH4Cl(s) ↔ NH3(g) + HCl(g)