I was able to answe the first $4,$ I am stuck on $5.$ What is the $pH$ of a $0\mathrm{.}050M$ ammonia $(N{H}_3)$ solution? $(K_b=1\mathrm{.}8**{10}^{-5})$

What is the $pH$ of a solution where $50\mathrm{.}0mL$ of $0\mathrm{.}050MN{H}_3$ is mixed with $12\mathrm{.}0$

$mL$ of $0\mathrm{.}10M$ hydrobromic acid $(HBr)?$

What is the $pH$ at the $\frac{1}{2}$ equivalence point?

What is the $pH$ of a titration of $50\mathrm{.}0mL$ of $0\mathrm{.}050MN{H}_3$ with $0\mathrm{.}10MHBr$ once

the equivalence point is reached?

$($HINT: Start by calculating the volume of $HBr$ needed to reach the equivalence point.$)$

What is the $pH$ of a solution where $50\mathrm{.}0mL$ of $0\mathrm{.}050MN{H}_3$ is mixed with $25\mathrm{.}1$

$mL$ of $0\mathrm{.}10MHBr?$

$B^{-}+H_{2}OHB+OH,\frac{x^2}{0\mathrm{.}05},=1\mathrm{.}8{10}^{-5}$

$0\mathrm{.}05m+x+x,0\mathrm{.}05$

$-x,x,=9\mathrm{.}486{10}^{-4}$

$-log(x),=3\mathrm{.}02$pOH

$14,-3\mathrm{.}02=10\mathrm{.}98pH$

$[2.]$

$HBr+N{H}_{3}N{H}_4+Br$

$D.$ nolzmel $0\mathrm{.}00$sna $0.,N{H}_3=0\mathrm{.}021M$

$\frac{0,0012}{0(mol)}\frac{0,0012}{\frac{0\mathrm{.}0013(mol)}{0\mathrm{.}0621}}\frac{+0,0012md}{0,0012(mol)},N{H}_4=0\mathrm{.}019M$

POH $=-log(1\mathrm{.}8{10}^{-5})+log(\frac{0\mathrm{.}021}{0\mathrm{.}019})$

polt $=4,78$

$pH=9,22$

$\frac{1{10}^{-14}}{1\mathrm{.}8{10}^{-5}}=5\mathrm{.}56{10}^{-10}=kq$

$-log(5\mathrm{.}56{10}^{-10})=9\mathrm{.}26pH$

$\frac{c\mathrm{.}0025md}{0\mathrm{.}075(L)}=0\mathrm{.}033m,\frac{1{10}^{-401}}{1\mathrm{.}6{10}^{-3}}=5\mathrm{.}56{10}^{-10},-1ng(\frac{1}{x})$

$=5\mathrm{.}37pH$

$[5]N{H}_3+HBrNHY$

$0,0025e,002s1$

$\frac{-0,0025}{0}\frac{0,0025}{0,00001},\frac{t_{0,0025}}{0\mathrm{.}0025}($