Given that the dissociation constant for $H_2O$ is $K_w = 1 \times 10^{-14} \ mol^2 \ L^{-2}$,what is the $pH$ of a $0.001 \ M \ KOH$ solution?

$75 \ mL$ of $0.2 \ M \ HCl$ is mixed with $25 \ mL$ of $1 \ M \ HCl$. To this solution, $300 \ mL$ of distilled water is added. What is the $pH$ of the resultant solution?

Equal volumes of three acid solutions of $pH$ $3$,$4$ and $5$ are mixed in a vessel. What will be the $H^{+}$ ion concentration in the mixture in terms of $\times 10^{-4} \ M$?

The $pH$ of the solution obtained by mixing $100 \ mL$ of a solution of $pH=3$ with $400 \ mL$ of a solution of $pH=4$ is

Which of the following solutions has the highest $pH = 14$?

The number of moles of $Ca(OH)_2$ required to prepare $250 \ mL$ of solution with $pH$ $14$ (assuming complete ionization) is :-