Water Quality Parameters MCQ with answer and solution

Concept

Decaying organic (peaty) matter dissolves in water and gives it a yellowish-brown colour.

Step-by-step solution

1. Peaty land has a lot of decaying vegetable matter. 2. Humic and tannic substances from this matter dissolve in the stream water. 3. These substances give the water a yellowish-brown, tea-like colour. 4. So the answer is brown.

Explanation

Water flowing through peat or swampy land picks up dissolved organic matter such as humic acids. This gives it a yellowish-brown colour. Colour in water is measured on the platinum-cobalt scale.

Why the other options are wrong

A: Black is not the typical colour of peaty water. B: Blue is the natural tint of deep, clear water, not peaty water. D: Some books say yellowish, but the more common description is brown.

Shortcut

Peat = decaying plants = tea-like brown water.

Common mistake

Choosing yellow because some books write 'yellowish-brown'.