Question

The figure shows an electrolyte of AgCl through which a current is passed. It is observed that 2.68 g of silver is deposited in 10 minutes on the cathode. Find the heat developed in the 20 Ω resistor during this period. Atomic weight of silver is 107.9 g mol⁻¹.

Answer 1

Given:
Mass of silver deposited, m = 2.68 g
Time, t = 10 minutes = 600 s
Using the formula, m = Zit, we get:
$$\begin{gathered} 2.68\times {10}^{-3}=\frac{107.9\times {10}^{-3}}{96500}\times i\times 600 \\ \Rightarrow i=\frac{2.68\times 96500}{107.9\times 600} \\ \Rightarrow i=3.99=4\mathrm{A} \end{gathered}$$

Heat developed in the 20 Ω resistor,
$$\begin{gathered} H=i^{2}Rt \\ \Rightarrow H={\left(4\right)}^2\times 20\times 600 \\ \Rightarrow H=192000\mathrm{J}=192\mathrm{kJ} \end{gathered}$$