Question

A copper plate of $10cm\times 10cm$ and $0.1cm$ thickness is to be plated with silver. If the density of $Ag$ is $10.8g/cc$, then the number of moles of electrons required for this process is:

• A. 1 mole
• B. 2 moles
• C. 0.5 moles
• D. 2.5 moles

Answer 1

The correct option is A 1 mole

Area of the copper plate $\left(A\right)=10\times 10c{m}^2$.
Thickness $\left(t\right)=0.1cm$.
Volume$=10\times 10\times 0.1c{m}^3=10c{m}^3$.
$\therefore$ Amount of silver $=density\times volume=\frac{10.8g}{cc}\times 10cc=108g$.
$\therefore$ Mole of silver $=\frac{108}{108}=1$ mole.
$A{g}^{+}+e^{-}\to Ag$
$\therefore$ 1 mole $A{g}^{+}$ requires 1 mole of $e^{-}$.

Option A is correct.