A $20\mathrm{.}0mL$ aliquot of $0\mathrm{.}100MN{H}_3$ is titrated with $0\mathrm{.}100MHCl.($a$)$ What is the $pH$ of the solution before titration? $($b$)$ What is the $pH$ of the solution

after $10\mathrm{.}0mL$ of $HCl$ has been added? $($c$)$ What is the $pH$ of the solution at

equivalent point $($after $20\mathrm{.}0mL$ of $0\mathrm{.}100MHCl$ is added$)?$

$(K{b}_{b}N{H}_3=1\mathrm{.}8{10}^{-5})$