Determine the concentration of $H^{+}$in each solution at $25C.$

A solution with $pH=2\mathrm{.}0.$

$H^{+}$

A solution with $pH=6\mathrm{.}0.$

$[H^{+}]=$

A solution with pOH$=10\mathrm{.}0.$

$[H^{+}]=$Calculate the $O{H}^{-}$and the $pH$ of a solution with an $[H^{+}]=0\mathrm{.}00099M$ at $25C$

Calculate the $H^{+}$and the $pH$ of a solution with an $[O{H}^{-}]=0\mathrm{.}020M$ at $25C.$

Calculate the $H^{+}$and the $O{H}^{-}$of a solution with a $pH=8\mathrm{.}81$ at $25C.$

$[O{H}^{-}]=$