Calculate the $pH$ for each of the cases in the titration of $25\mathrm{.}0mL$ of $0\mathrm{.}170M$ pyridine, $C_5{H}_{5}N(aq)$ with $0\mathrm{.}170MHBr(aq).$ The $K_b$ of pyridine is $1\mathrm{.}7{10}^{-9}.$

before addition of any $HBr,pH=$

after addition of $12\mathrm{.}5mL$ of $HBr,pH=$

after addition of $22\mathrm{.}0mL$ of $HBr,pH=$

after addition of $25\mathrm{.}0mL$ of $HBr,pH=$

after addition of $31\mathrm{.}0mL$ of $HBr,pH=$