For a weak acid $HA$ with dissociation constant $10^{-9}$,the $pOH$ of its $0.1 \ M$ solution is:

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

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

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

The degree of dissociation of $0.1 \, N \, CH_3COOH$ is (Dissociation constant $K_a = 1 \times 10^{-5}$)

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 $M$)?