Question

Determine the $pH$ of $0.024 \,M$ hydroxylamine hydrochloride solution. ($K _{b}$ of hydroxyl amine is $10^{-8}$).

• A. 8.4
• B. 6.2
• C. 3.8
• D. 5.6

Answer 1

Answer: (C)

$HO\overset{+}{N}H _{3}+ H _{2} O \rightleftharpoons HONH _{3} OH + H ^{+}$
$K_{h}=\frac{K_{ w }}{k_{b}}=\frac{10^{-14}}{10^{-8}}=10^{-6}$
$\left[ H ^{+}\right]=\sqrt{K_{h} C}$
$=\sqrt{10^{-6} \times 0.024}$
$=1.5 \times 10^{-4}$
and $pH =3.8$