The percentage dissociation of a decinormal solution of a weak acid $HA$ is: $(K_a = 4.9 \times 10^{-8})$

If the $pH$ of $0.10 \ M$ monoacidic base at $298 \ K$ is $9.0$,the value of $K_{b}$ and $pK_{b}$ at the same temperature are respectively:

The $pH$ of a $0.1 \ M$ aqueous solution of a very weak acid $(HA)$ is $3$. What is its degree of dissociation in percentage?

The $pH$ of $0.1 \, M$ solution of cyanic acid $(HCNO)$ is $2.34$. Calculate the ionization constant of the acid and its degree of ionization in the solution.

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 $M$)?

Dissociation constant for a monobasic acid is $10^{-4}$. What is the $pH$ of the monobasic acid? (If $\%$ dissociation $= 2\,\%$)