The purest form of water in nature is -

Correct option is A

Ans. (a) Rainwater
Explanation:
Rainwater is the purest natural form of water because it is directly condensed from water vapor in the atmosphere through the hydrological cycle, free from dissolved impurities.
Why is Rainwater the Purest Form of Water?
1. Formed by Evaporation & Condensation:
· Rainwater originates from evaporation of surface water (oceans, lakes) and condenses into pure water droplets, leaving behind most dissolved minerals, salts, and impurities.
2. No Dissolved Salts or Minerals:
· Unlike groundwater or surface water, rainwater does not contain significant amounts of dissolved solids (like calcium, magnesium, or iron).
3. Low in Contaminants (Before Reaching the Ground):
· When rainwater first falls, it is almost chemically pure (H₂O).
· However, as it passes through the atmosphere, it may absorb dust, pollutants, and gases like CO₂, SO₂, and NO₂, forming acid rain in polluted areas.
Why are the other options incorrect?
1. Rivers → (Incorrect Choice)
· River water contains dissolved minerals, sediments, organic matter, and pollutants from soil runoff and human activities.
· It is not as pure as rainwater.
2. Ponds → (Incorrect Choice)
· Ponds contain stagnant water, often contaminated with algae, microorganisms, organic waste, and sediments.
· High risk of bacterial growth and pollution.
3. Water from Deep Wells → (Incorrect Choice)
· Groundwater from deep wells contains dissolved minerals (calcium, magnesium, iron, fluorides, etc.) due to prolonged contact with rocks and soil.
· Requires filtration and treatment to remove impurities.