When common salt is added of a saturated solution of soap is precipitate(d)This is based on the principle of

Step-by-step solution

NaCl on dissociation gives Na ⁺ and Cl ⁻ ions as follows: Sodlum chloride NaCl (a q) Common ions Na ⁺ + Cl ⁻ (ions) While, soap in the solution gives RCOO ⁻ and Na ⁺ ions as follows: R- COONa (s) RCOO ⁻+ Na ⁺ where R- COONa (s) is soap Solubility of soap decrease due to common ion ( Na ⁺ ) present in the solution due to Le-Chatelier's principle, reaction shifts towards the reactant side.