1. Find moles of $\mathrm{O_2}$ displaced at STP

At STP, $1$ mole of gas occupies $22.4\,\mathrm{L} = 22400\,\mathrm{mL}$.

Given volume of oxygen: $5600\,\mathrm{mL} = 5.6\,\mathrm{L}$

So, moles of $\mathrm{O_2}$ are: $n(\mathrm{O_2}) = \frac{5600}{22400} = \frac{1}{4}\,\mathrm{mol}$

2. Relate oxygen evolved to electrons transferred

At the anode, oxygen is liberated as: $2\mathrm{H_2O} \rightarrow \mathrm{O_2} + 4\mathrm{H^+} + 4e^-$

Thus, $1$ mole of $\mathrm{O_2}$ corresponds to $4$ moles of electrons.

Therefore, $\frac{1}{4}$ mole of $\mathrm{O_2}$ corresponds to: $\frac{1}{4} \times 4 = 1\,\text{mol } e^-$

So the quantity of electricity passed is 1 Faraday.

3. Use this charge to find silver deposited

Silver is deposited according to: $\mathrm{Ag^+} + e^- \rightarrow \mathrm{Ag}$

Here, $1$ mole of electrons deposits $1$ mole of silver.

Since $1$ mole of electrons passed, moles of silver deposited: $n(\mathrm{Ag}) = 1\,\mathrm{mol}$

Mass of silver: $m = nM = 1 \times 108 = 108\,\mathrm{g}$

4. Final Answer

$\boxed{108}$