Addition of Alum in Water Treatment Increases

Answer: A. Acidity of water

Addition of alum in water treatment increases acidity of water.

Solution

The following chemical reaction takes place when alum is added to water and reacts with the alkalinity of water:

Al₂(SO₄)₃.18H₂O + 3Ca(HCO₃)₂ → 2Al(OH)₃ + 3CaSO₄ + 6CO₂

Alum reacts with the alkalinity present in water and leads to the formation of gelatinous aluminium hydroxide, and temporary hardness is eliminated. 

Addition of alum in water treatment increases the acidity of water as carbon dioxide gas is released, which leads to the formation of carbonic acid, thereby, increasing the acidity of water and decreasing the pH.

☛ Related Questions:

• The flow in a pipe is laminar if
• Straight, parallel and widely spaced contour represents
• The Load Stress of a Section can be reduced by
• Which of the following is not the component of harbour?