Introduction:
In the process of electrolysis, the chemical effect of electric current is observed. Electrolysis is a process in which an electric current is passed through a substance to produce a chemical change. This process is used to break down compounds into their constituent elements or ions.

Why is alkali added before electrolysis to pure water?
Adding an alkali (such as sodium hydroxide or potassium hydroxide) to pure water before electrolysis serves two purposes:

1. Formation of ions: Pure water is a poor conductor of electricity because it contains a very small number of ions. By adding an alkali, the water becomes alkaline and the alkali dissociates into positive and negative ions. These ions improve the conductivity of the solution, allowing for the passage of electric current.

2. Purification of water: Alkalis are strong bases and have the ability to neutralize any acidic impurities present in the water. This helps in purifying the water before the electrolysis process.

The process of electrolysis:
The electrolysis of water involves the decomposition of water molecules into hydrogen gas (H2) and oxygen gas (O2) through the following reactions:

At the cathode (negative electrode):
2H2O(l) + 2e- → H2(g) + 2OH-(aq)

At the anode (positive electrode):
4OH-(aq) → O2(g) + 2H2O(l) + 4e-

Procedure:
1. Prepare a setup with two electrodes (one positive and one negative) immersed in a beaker containing the alkaline water solution.
2. Connect the positive electrode (anode) to the positive terminal of the power supply and the negative electrode (cathode) to the negative terminal.
3. Turn on the power supply to allow the electric current to flow through the solution.
4. As the current passes through the water, electrolysis occurs, and bubbles of hydrogen gas are formed at the cathode, while oxygen gas is formed at the anode.
5. The gases can be collected separately and tested for their properties.

Conclusion:
In conclusion, adding an alkali before electrolysis to pure water helps in improving the conductivity of the solution and purifying the water. This allows for the successful electrolysis of water, resulting in the production of hydrogen and oxygen gases. The process of electrolysis is an important application of the chemical effect of electric current.

Yes. because pure water is a bad conductor of electricity