The concentration of $[CN^{-}]$ in $0.1 \, M \, HCN$ solution is: $(K_a = 4 \times 10^{-10})$

At $25 \, ^\circ C$,the equilibrium constant for a base $BOH$ is $1.0 \times 10^{-12}$. What will be the concentration of hydroxide ions in a $0.01 \, M$ aqueous solution of the base?

Calculate the $pH$ of a $0.08 \ M$ solution of hypochlorous acid,$HOCl$. The ionization constant of the acid is $2.5 \times 10^{-5}$. Determine the percent dissociation of $HOCl$.

For a $0.1 \ M$ aqueous pyridine solution,if the pyridinium ion concentration is produced such that the degree of dissociation is $0.013 \%$,calculate the concentration of the pyridinium ion.

What is the $pH$ of $0.001 \,M$ aniline solution? The ionization constant of aniline can be taken from the table. Calculate the degree of ionization of aniline in the solution. Also,calculate the ionization constant of the conjugate acid of aniline.

Base	$K_{b}$
Dimethylamine,$(CH_{3})_{2}NH$	$5.4 \times 10^{-4}$
Triethylamine,$(C_{2}H_{5})_{3}N$	$6.45 \times 10^{-5}$
Ammonia,$NH_{3}$	$1.77 \times 10^{-5}$
Quinine	$1.10 \times 10^{-6}$
Pyridine,$C_{5}H_{5}N$	$1.77 \times 10^{-9}$
Aniline,$C_{6}H_{5}NH_{2}$	$4.27 \times 10^{-10}$
Urea,$CO(NH_{2})_{2}$	$1.3 \times 10^{-14}$

The degree of dissociation of acetic acid $(0.1 \ mol \ L^{-1})$ in water ($K_a$ of acetic acid is $10^{-5}$) is