$L$ 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 $2$?

Given $pH$ of a solution $A$ is $3$ and it is mixed with another solution $B$ having $pH$ $2$. If both are mixed in equal volumes,then the resultant $pH$ of the solution will be

The concentration of $NaOH$ solution is $10^{-8} \ M$. Find out the $[OH^{-}]$ concentration.

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?

Millimoles of calcium hydroxide required to produce $100 \ mL$ of the aqueous solution of $pH$ $12$ is $x \times 10^{-1}$. The value of $x$ is $..............$. (Nearest integer). Assume complete dissociation.

What is the $pH$ of $10^{-9} \ M$ aqueous $HCl$ solution?