Question

Assertion: The complete electrolysis of $1{\text{mol}}$ of water requires ${\text{2F}}$.
Reason: Faraday is the quantity of electric charge carried by $1{\text{mol}}$ of electrons.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
C. Assertion is correct but Reason is incorrect.
D. Assertion is incorrect but Reason is correct.

Answer 1

Electrolysis is the passage of a direct electric current through an ionic substance that is either molten or dissolved in a suitable solvent, resulting in chemical reactions at electrodes and separation of materials. Electrolyte is decomposed during electrolysis.

Complete step by step solution:
Electrolysis is used to separate a metal from its compound.
Requirements of electrolysis are:
1.Electrolyte is a substance containing free ions which are the carriers of electric current in the electrolyte.
2.A DC current provides the electrical energy necessary to create or discharge the ions in the electrolyte. Electrical current is carried by electrons in the external circuit.
3.Two electrodes-Electrode is an electrical conductor which provides a physical interface between the electrical circuit providing energy and the electrolyte.

When an ionic compound is melted or dissolved, then the ions become free to move around and carry electrical current. The electrons move from anode to cathode. Electrolytes dissociate to form anions and cations. Eventually, salts and gases are liberated at these electrodes.
At anode: $2{{\text{H}}_2}{\text{O}} \to {{\text{O}}_2} + 4{{\text{H}}^ + } + 4{{\text{e}}^ - }$
At cathode: $4{{\text{H}}^ + } + 4{{\text{e}}^ - } \to 2{{\text{H}}_2}$
Total: $2{{\text{H}}_2}{\text{O}} \to 2{{\text{H}}_2} + {{\text{O}}_2}$
From the reaction, it is obvious that $1\,{\text{mol}}$ of water needs two moles of electrons. One faraday is the charge of one mole of electrons. So it can be said that $1\,{\text{mol}}$ of water needs ${\text{2F}}$ .
i.e. complete electrolysis of $1\,{\text{mol}}$ of water occurs in ${\text{2F}}$.
Hence Assertion and Reason are correct.

So the correct option is A.

Note: During electrolysis, at the positive electrode, namely anode, the negative ions lose electrons which is called oxidation. At the negative electrode, namely cathode, the positive ions gain electrons which is called reduction.