What is the $[OH^{-}]$ in the final solution prepared by mixing $20.0 \ mL$ of $0.050 \ M \ HCl$ with $30.0 \ mL$ of $0.10 \ M \ Ba(OH)_2$? $...... \ M$

What would happen when a solution of potassium chromate is treated with an excess of dilute nitric acid?

$A$ certain amount of $H_2CO_3$ and $HCl$ are dissolved to form $1 \ L$ solution. At equilibrium,it is found that the concentrations of $H_2CO_3$ and $CO_3^{2-}$ are $0.1 \ M$ and $0.01 \ M$ respectively. Calculate the $pH$ of the solution. Given that for $H_2CO_3$,$K_{a_1} = 10^{-5}$ and $K_{a_2} = 10^{-8}$.

The first and second dissociation constants of a diprotic acid ${H_2}A$ are $1.0 \times 10^{-5}$ and $5.0 \times 10^{-10}$ respectively. The overall dissociation constant of the acid ${H_2}A$ is .......

For the reaction in aqueous solution $Zn^{2+} + X^{-} \rightleftharpoons ZnX^{+}$,the $K_{eq}$ is greatest when $X$ is

The correct order of increasing $[H_3O^{+}]$ in the following aqueous solutions is: