How much electricity in terms of Faraday is required to produce
(i) 20.0 g of Ca from molten CaCl2.
(ii) 40.0 g of Al from molten Al2O3.
(i) According to the question,
CA2+ + 2e-1 \(\rightarrow\) Ca
40 g
Electricity required to produce 40 g of calcium = 2 F
Therefore, electricity required to produce 20 g of calcium =\(\frac{2 \times 20}{4}\) F
= 1 F
(ii) According to the question,
Al3+ + 3e- \(\rightarrow\) Al
27 g
Electricity required to produce 27 g of Al = 3 F
Therefore, electricity required to produce 40 g of Al = \(\frac{3 \times 40}{27}\) F
= 4.44 F
Galvanic cells, also known as voltaic cells, are electrochemical cells in which spontaneous oxidation-reduction reactions produce electrical energy. It converts chemical energy to electrical energy.
It consists of two half cells and in each half cell, a suitable electrode is immersed. The two half cells are connected through a salt bridge. The need for the salt bridge is to keep the oxidation and reduction processes running simultaneously. Without it, the electrons liberated at the anode would get attracted to the cathode thereby stopping the reaction on the whole.