• # question_answer Solution of $0.1\,N\,N{{H}_{4}}OH$and $0.1\,N\,N{{H}_{4}}Cl$has pH 9.25, then find out $p{{K}_{b}}$of $N{{H}_{4}}OH.$ A)  9.25         B)  4.75C)  3.75         D)  8.25

Solution of $N{{H}_{4}}OH$and $N{{H}_{4}}Cl$acts as a basic buffer solution. For basic buffer solution $pOH=p{{K}_{b}}+\log \frac{[salt]}{[Base]}$ $pOH=14-pH=14-9.25=4.75$ $4.75=p{{K}_{a}}+\log \frac{0.1}{0.1}$ $p{{K}_{a}}=4.75$