Select the $pK_a$ value of the strongest acid from the following.

The $K_a$ of a weak acid $HA$ is $1.00 \times 10^{-5}$. If $0.100 \ mol$ of this acid is dissolved in $1 \ L$ of water,what is the percentage dissociation of the acid at equilibrium?

For a weak base $BOH$ at $25\,^oC$,the dissociation constant $K_b$ is $1.0 \times 10^{-12}$. The concentration of hydroxyl ions in its $0.01\,M$ aqueous solution will be:

Calculate the ionisation constant of $0.08 \ mol \ dm^{-3}$ of a monobasic acid having $pH = 2$.

Find the $pOH$ value of $10^{-3} \ M \ NH_4OH$. Given $K_b = 10^{-5}$.

The ionization constant of $0.1$ $M$ weak acid is $1.74 \times 10^{-5}$ at $298$ $K$ temperature. Calculate the $pH$ of its $0.1$ $M$ solution. (in $.88$)