$L$ litres of water must be added to $1 \, L$ of an aqueous solution of $HCl$ with a $pH$ of $1$ to create an aqueous solution with $pH$ of $2$?

$0.023 \ g$ of sodium metal is reacted with $100 \ cm^{3}$ of water. The $pH$ of the resulting solution is

When $100 \ mL$ of $0.1 \ M$ $NaOH$ is added to $50 \ mL$ of $0.2 \ M$ $HCl$ at $25 \ ^oC$,the $pH$ of the resulting solution will be:

$0.001 \ mol$ of a strong electrolyte $M(OH)_2$ is dissolved to make $20 \ mL$ of a saturated solution. Calculate its $pH$ $(K_w = 1 \times 10^{-14})$.

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

If $0.561 \, g$ of $KOH$ is dissolved in water to give $200 \, mL$ of solution at $298 \, K$. Calculate the concentrations of potassium,hydrogen and hydroxyl ions. What is its $pH$?