At $25 \, ^oC$,the concentration of $H^{+}$ and $OH^{-}$ ions in pure water is $1 \times 10^{-7} \, M$ each. Which of the following is equal to $2 \times 10^{-7} \, M$?

When a standard solution of $NaOH$ is left in the air for a few hours,

Which of the following pairs of substances cannot exist together in a solution?

The first and second dissociation constants of a diprotic acid $H_2A$ are $1.0 \times 10^{-5}$ and $5.0 \times 10^{-10}$ respectively. The overall dissociation constant of the acid is:

The ionization constant of propanoic acid is $1.32 \times 10^{-5}$. Calculate the degree of ionization of the acid in its $0.05 \, M$ solution and also its $pH$. What will be its degree of ionization if the solution is $0.01 \, M$ in $HCl$ also?

In a saturated solution of $Mg(OH)_2$,the degree of dissociation of $Mg(OH)_2$ is $\alpha$. Find the concentration $(C)$ of $Mg(OH)_2$ if the concentration of $[OH^{-}]$ is $2$.