Calculate the concentration of a weak monobasic acid if its degree of dissociation and dissociation constant are $5.0 \times 10^{-4}$ and $5.0 \times 10^{-9}$ respectively (in $M$)?

$A$ weak acid is $0.1\%$ ionised in $0.1 \ M$ solution. Its $pH$ is

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]

The dissociation constant of a weak monobasic acid is $3.2 \times 10^{-4}$. Calculate the degree of dissociation in its $0.04 \ M$ solution.

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

The degree of ionization of $0.4 \ M$ acetic acid will be $(K_{a} = 1.8 \times 10^{-5})$.