The ( p K_a ) of a weak acid, benzoic acid and ( p K_b ) of a weak base, ammonium hydroxide are 4.25 and 4.75 respectively. Then the ( pH ) of (0.1 M ) solution of ammonium benzoate will be

Step-by-step solution

Ammonium benzoate ( ( C ₆ H ₅ COONH ₄ ) ) is the salt weak benzoic acid ( ( C ₆ H ₅ COOH , p K_a=4.25 ) ) and weak ammonium hydroxide ( ( NH ₄ OH , p K_b=4.75 ) ). So, ( pH ) of the solution of ( C ₆ H ₅ COONH ₄ ) will be, ( aligned pH & =7+ 1 2 ( p K_a- p K_b ) & =7+ 1 2 (4.25-4.75)=7-0.25=6.75 aligned )