To the given post option \"d\" is correct answer. The reason is that added the salt to BaSO4 the solubility get increased . in the second case ammonia will react with water form ammoniumhydroxide later it dissociated as ammonium ion and hydroxide ion . So H+ ion concentration will decreased. Solution To the given post option \"d\" is correct answer. The reason is that added the salt to BaSO4 the solubility get increased . in the second case ammonia will react with water form ammoniumhydroxide later it dissociated as ammonium ion and hydroxide ion . So H+ ion concentration will decreased..