Which out of the following does not help in disinfecting water?

Question

Accepted Answer

The correct answer is **3. Alums**.

### Explanation:

Disinfection of water is a process aimed at eliminating pathogens and harmful microorganisms to make water safe for drinking and other uses. Let's analyze each option:

1. **Filtration**: This process involves passing water through a filter to remove impurities, including bacteria and other pathogens. While filtration can reduce the number of microorganisms, it does not necessarily kill them. However, it is often used in conjunction with other disinfection methods.

2. **Chlorine tablets**: Chlorine is a well-known disinfectant that effectively kills bacteria, viruses, and other pathogens in water. Chlorine tablets release chlorine when dissolved in water, making them a direct method of disinfection.

3. **Alums**: Alum (aluminum sulfate) is primarily used as a coagulant in water treatment processes. It helps in the removal of suspended particles by causing them to clump together (coagulation) and settle out of the water. While it improves water clarity and can aid in the removal of some pathogens by helping them to be filtered out, it does not disinfect water by killing microorganisms.

4. **Boiling**: Boiling water is one of the most effective methods of disinfection. The high temperature kills most pathogens, including bacteria, viruses, and protozoa, making the water safe for consumption.

### Conclusion:

Among the options provided, **alums** do not serve as a disinfectant. Instead, they play a role in the coagulation process, which can help in the removal of particles but does not kill pathogens. Therefore, the correct answer is **3. Alums**.