The percent dissociation of a weak monobasic acid is $3 \%$ in its $0.02 \ M$ solution. What is the dissociation constant of the acid?

$A$ weak monobasic acid dissociates to $0.001 \%$ in its $0.01 \ M$ solution. What is its dissociation constant?

What is the value of $pH$ of a $NaOH$ solution that dissociates $2 \%$ in its $0.01 \ M$ solution?

Consider the dissociation equilibrium of the following weak acid $HA \rightleftharpoons H^{+}_{(aq)} + A^{-}_{(aq)}$. If the $pK_{a}$ of the acid is $4$, then the $pH$ of $10 \ mM$ $HA$ solution is . . . . . . . (Nearest integer)
[Given : The degree of dissociation can be neglected with respect to unity]

In $20 \, mL$ of $0.4 \, M$ $HA$ solution,$80 \, mL$ of water is added. Assuming volume to be additive,the $pH$ of the final solution is ($K_a$ of $HA = 4 \times 10^{-7}, \log 2 = 0.3$).

$A$ weak monoacidic base dissociates to $1.5 \%$ in $0.001 \ M$ solution at $298 \ K$. Calculate the dissociation constant of the weak base.