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

In a reversible reaction, if the concentration of reactants are double, the equilibrium constant K will be x times the initial equilibrium constant. x will be equal to

Presence of catalysis does not change equilibrium constant. Why?

At a given temperature, for a reversible reaction, if the concentration of reactants is doubled then the equilibrium constant will

In which of the following reactions, the concentration of product is higher than the concentration of reactant at equilibrium? (K = equilibrium constant)

The maintenance of equilibrium of concentration of liquids is

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

Pure will can be obtained from sea water by