Finding the charge passed in electrolysis of water using volume of hydrogen released
$PV = nRT$ and $\ce{2H+ + 2e- -&gt; H2}$ are your best friends.
Step 1: Find the number of moles of hydrogen gas released
Use the formula: $PV = nRT$, where $P =$ Pressure exerted by the
gas, $V =$ Volume of gas, $n = $ number of moles of gas, $R = $ universal gas constant, $T = $ temperature of gas.
Using this formula with $P$ in atm and $V$ in liters we get:
$$n =\frac{PV}{RT} = \pu{0.0044 mol}$$
Step 2: Find the number of farads of charge used
We know that $$\ce{2H+ + 2e- -&gt; H2}$$
This means that for every mole of hydrogen released, $\pu{2 moles}$ of electrons are used. A farad is the charge on $\pu{1 mol}$ of electrons and so number of farads of would be two times the number of moles of electrons. So charge would be $\pu{0.0088 F}$.
Step 3: One farad = 96500 coulombs
Therefore, $\pu{0.0088 F = 850.32 C}$ and that should be the answer.