$(i)$ What is the $pH$ range for a base?
$(ii)$ How can the strength of a basic solution be increased?

(N/A) $(i)$ The $pH$ range of a base is greater than $7$ and up to $14$.
$(ii)$ The strength of a base depends on the concentration of $OH^{-}$ ions in the solution. Therefore,the strength of a basic solution can be increased by increasing the concentration of $OH^{-}$ ions.