$40 \, mg$ of pure sodium hydroxide is dissolved in $10 \, L$ of distilled water. The $pH$ of the solution is

Which of the following will decrease the $pH$ of a $50 \ mL$ solution of $0.01 \ M \ HCl$?

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

Calculate the $pH$ of a $0.002 \ M$ $KOH$ solution.

The $pH$ of $0.01 \ N$ lime water is:

Equal volumes of two solutions $A$ and $B$ of a strong acid having $pH=6.0$ and $pH=4.0$ respectively are mixed together to form a new solution. The $pH$ of the new solution will be in the range