Question

describe electrolysis briefly best one will be marked as brainlist

Answer 1

Electrolysis of Molten Salts. Electrolysis is a process by which electrons are forced through a chemical cell, thus causing a chemical reaction. The positive charge usually attracts electrons, and the electrode providing electrons is called cathode, because reduction takes place on it.

Answer 2

Definition: Process of decomposition of an electrolyte when electricity is passed through its aqueous solution or, its melt (fused state). Electrical energy is used to drive an otherwise non-spontaneous redox reaction. The apparatus used to bring about electrolysis is called an electrolytic cell.

Setup: The electrolyte in the form of aqueous solution or in the molten state is taken. 2 metal rods (called electrodes) are dipped into it. The rods are connected to an external source of electricity (battery).

Rod connected to negative pole = cathode

Rod connected to positive pole = anode

Theory: Ionization theory

It says that whenever an electrolyte (acid, base or salt) is dissolved in water or taken in the molten state, the electrolyte dissociates to produce +vely and -vely charged ions.

Mechanism: On passing electricity, the the +vely charged ions move towards the -ve cathode and the -vely charged ions move towards the +ve anode. Thus called cations and anions, respectively. After they reach their respective electrodes, ions lose their charge to become neutral species. The cations accept electrons and the anions lose electrons for this. So, oxidation takes place “at” the anode and reduction takes place “at” the cathode.

The conversion of ions into neutral species is called primary change.

The product formed due to primary change may either just get collected or undergo secondary change to form the final products.

Example: Taking NaCl as the electrolyte. In the molten state, it exists as Na+ and Cl- ions. When electricity is passed, the Na+ cations move towards the cathode and the Cl- anions move towards the anode. Since the cathode is linked to the negative terminal of the battery, it is negative and the cation accepts electrons from it. Reduction takes place here.

Na+ + e- → Na …………………………..(primary change)

The Cl- anions move towards the anode and give electrons to the anode. Thus, oxidation takes place here.

Cl- → Cl. (free radical) + e- …………(primary change)

Cl. + Cl. → Cl2 (gas) …………………..(secondary change)

Overall reaction:

2Na+ + 2Cl- → 2Na + Cl2

or, 2NaCl → 2Na + Cl2