The active mass for any pure liquid or pure solid

Assertion (A) : The active mass of pure solid and pure liquid is taken unity. Reason (R) : The active mass of pure solids and liquids depends on the density and molecular mass. The density and molecular of a mass of pure liquids and solids are constant.

Assertion (A) : The active mass of pure solid and pure liquid is taken unity. Reason (R) : The active mass of pure solids and liquids depends on the density and molecular mass. The density and molecular of a mass of pure liquids and solids are constant.

Why the concentrations of pure liquids and pure solids are ignored from equilibrium constant expressions?

The following are some statements about active masses. A) Active mass of pure liquids and solids are taken as unity B) Active mass of electrolytes is taken as molality C) For dilute solutions of non-electrolytes, the active mass can be taken as molarity The correct combination is