question_answer

Why common salt is added to precipitate out soap from the solution during its manufacture?

Answer:

                Soap is sodium salt of higher fatty acids (RCOONa). On adding common salt, \[N{{a}^{+}}\] ion concentration increases. Hence, the equilibrium \[RCOONa(s)\rightleftharpoons \,RCO{{O}^{-}}+N{{a}^{+}}\] shifts in the backward direction, i.e., soap precipitates out.