1. Assertion (A): Synthetic detergents can lather well in hard water. 2. Reason (R): Synthetic detergents form soluble calcium and magnesium salts with hard water.

1. Assertion (A) states that synthetic detergents can lather well in hard water. This is true. Unlike traditional soaps, synthetic detergents generally maintain their cleaning effectiveness and ability to form lather even in hard water. 2. Reason (R) states that synthetic detergents form soluble calcium and magnesium salts with hard water. This is also true. Hard water contains dissolved calcium (Ca2+) and magnesium (Mg2+) ions. Soaps react with these ions to form insoluble precipitates (scum), reducing lathering and cleaning efficiency. However, synthetic detergents (like alkylbenzene sulfonates) react with Ca2+ and Mg2+ ions to form salts that are generally soluble in water. This prevents scum formation and allows the detergent to function effectively. 3. Since the ability of detergents to form soluble salts with hardness ions (R) is the reason why they can lather well in hard water (A), R is the correct explanation of A. 4. Therefore, Both A and R are individually true and R is the correct explanation of A.