Question

The rain water is -

• A. Impure
• B. Pure
• C. Salted
• D. None of these

Hint:

Rainwater is naturally distilled water—pure at formation. However, atmospheric pollution can make it impure before reaching ground. In clean environments, rainwater is safe for drinking after filtration.

Answer 1

The Correct Option is B

Rainwater is formed through the natural process of evaporation and condensation, making it one of the purest forms of naturally occurring water. Why Rainwater is Pure:

Formation Process:

Sun heats surface water (oceans, lakes, rivers) causing evaporation
Water turns into vapor, leaving behind impurities, salts, and minerals
Vapor rises, cools, and condenses to form clouds
When condensation occurs, pure water droplets form and fall as rain

Distillation Effect: The water cycle acts like natural distillation—impurities are left behind during evaporation
Important Considerations:

Theoretically Pure: Freshly evaporated and condensed rainwater is pure H₂O
Atmospheric Contamination: As rain falls through the air, it may dissolve:

Gases (CO₂, SO₂, NOₓ) → can form weak acids
Dust particles
Pollutants (especially in industrial areas)

Acid Rain: In polluted areas, rain may contain sulfuric/nitric acids
First Rain: Initial rain (first few minutes) washes atmospheric impurities; later rain is cleaner
Why Other Options are Incorrect:

(A) Impure: Not entirely correct—rainwater is pure at formation; impurities are acquired during fall
(C) Salted: Incorrect—salt does not evaporate; seawater evaporation leaves salt behind
(D) None of these: Incorrect because rainwater is essentially pure water
Purity Comparison: \begin{tabular}{|l|l|} \hline Water Type & Purity Level
\hline Rainwater (fresh) & Very pure (near distilled)
Distilled water & Purest
River water & Contains dissolved minerals
Sea water & High salt content
\hline \end{tabular} Final Answer: Pure