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

The degree of ionization of $0.10 \ M$ lactic acid is $4.0 \%$. The value of $K_a$ 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 ionisation constant of acetic acid is $1.8 \times 10^{-5}$. The concentration at which it will be dissociated to $2\%$,is (in $M$)

The dissociation constant of a weak monobasic acid is $2.7 \times 10^{-5}$. If the degree of dissociation of the acid is $3 \times 10^{-2}$,what is the concentration of the acid (in $M$)?

$A$ weak base is $1.3\%$ dissociated in its aqueous solution. If $K_b$ for the weak base is $1.69 \times 10^{-5}$ at $298 \text{ K}$, find the concentration of the aqueous solution of the weak base. (in $\text{ M}$)