What is the $pH$ of a $1 \ mM$ solution of $NaOH$?

Calculate the $pH$ of $1.0 \times 10^{-8} \ M \ NaOH$ solution.

What is the $pH$ of $0.005 \ M \ H_2SO_4$ solution?

When $10 \ mL$ of $0.1 \ M \ HCl$ and $40 \ mL$ of $0.2 \ M \ H_2SO_4$ solutions are mixed,the $pH$ of the resulting mixture will be:

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?

$A$ base dissolved in water yields a solution with a hydroxyl ion concentration of $0.05 \ mol \ L^{-1}$. The solution is