Question

Draw the diagram of electrolytic cell and explain

Answer 1

An electrolytic cell is an electro chemical cell that drives a non spontaneous redox reaction through the application of electrical energy. They are often used to decompose chemical compounds in a process called electrolysis - the Greek word lysis means break up. Important examples of electrolysis are decomposition of water into hydrogen and oxygen , bauxite into aluminium and other chemicals. Electroplating is done using an electrolytic cell. An electrolytic cell has 3 component parts : an electrolyte and 2 electrodes (cathode and anode). The electrolyte is usually a solution of water or other solvents in which ions are dissolved. Molten salts such as sodium chloride are also electrolytes. When driven by an external voltage applied to the electrodes , the ions in the electrolyte are attached to an electrode with the opposite charge , where charge transferring (also called faradaic or redox) reactions can take place. Only with an external electric potential (i.e voltage) of correct polarity and sufficient magnitude can an electrolytic cell decompose a normally stable , or inert chemical compound in a solution. The electrical energy provided can produce a Chemical reaction which would not occur spontaneously.

Answer 2

• It is a device that converts electrical energy into chemical potential energy. The process is called electrolysis.
• The cell consists of two metallic or electronic conductors (electrodes) held apart from each other and in contact with an electrolyte, usually a dissolved or fused ionic compound.
• Electrolytic cells are non spontaneous i.e. energy is consumed for reaction to proceed. Here electrical energy is used. So ΔG = +ve
• During the process tha cations(positive charged) are collected at cathode(negative electrode) and anions(negative charged) are collected at anode(positive electrode) where oxidation takes place.
• Example:

ELECTROLYSIS OF MOLTEN NaCl

NaCl ---(electrolysis)--> $Na^{+}$ + $Cl^{-}$

$Na^{+}$ is collected at cathode

$Cl^{-}$ is collected at anode

At cathode (reduction occurs)

$Na^{+}$ + $e^{-}$ ------> Na

At anode (oxidation ooccurs)

$Cl^{-}$ ------> $\frac{1}{2} Cl_{2}$ + $e^{-}$