The $pH$ of $1 \ L$ of an aqueous solution of $HCl$ is $1$. How many liters of water must be added to make the $pH$ of this solution $2$ (in $L$)?

What is the $pH$ of the resulting solution when equal volumes of $0.1 \ M \ NaOH$ and $0.01 \ M \ HCl$ are mixed?

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

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

$10^{-6} \ M \ NaOH$ is diluted $100$ times. The $pH$ of the diluted base is

Five solutions of $KOH$ are prepared as follows: $1st \to 0.1 \ mol$ in $1 \ L$,$2nd \to 0.2 \ mol$ in $2 \ L$,$3rd \to 0.3 \ mol$ in $3 \ L$,$4th \to 0.4 \ mol$ in $4 \ L$,$5th \to 0.5 \ mol$ in $5 \ L$. What is the $pH$ of the resulting mixture?