The ionization constant of benzoic acid is $6.5 \times 10^{-5}$ at $298 \ K$ temperature. Calculate $pH$ of its $0.15 \ M$ solution. (in $.5$)

What is the molar concentration of a weak monobasic acid if its dissociation constant is $5 \times 10^{-8}$ and it undergoes $0.5 \%$ dissociation (in $M$)?

The $pH$ of a $0.1 \ M$ solution of the acid $HQ$ is $3$. The value of the ionization constant,$K_a$ of the acid is:

$A$ weak monobasic acid is $3.0 \%$ dissociated in its $0.04 \ M$ solution. What is the dissociation constant of the acid?

The dissociation constant of a monoacidic weak base $MOH$ is $1.8 \times 10^{-5}$. What is the concentration of $OH^{-}$ ions in its $0.1 \, M$ solution?

The dissociation constants of monobasic acids $A$,$B$,$C$ and $D$ are $6 \times 10^{-4}$,$5 \times 10^{-5}$,$3.6 \times 10^{-6}$ and $7 \times 10^{-10}$ respectively. The $pH$ values of their $0.1 \ M$ aqueous solutions are in the order