Distillation purifies water by evaporation and condensation

Steps:

• Identify impurities in river water: dissolved salts, microbes, organics, and particles.
• Evaluate each process: check if it removes all impurity types to yield pure H2O.
• Adding chlorine kills microbes but leaves dissolved solids.
• Filtering traps particles but not dissolved ions.
• Distillation evaporates water (boiling point 100°C), leaving non-volatile impurities; condensed vapor is pure.
• Carbon adsorption removes organics but not salts or microbes fully.

Why C is correct:

• Distillation separates based on boiling point differences, yielding 100% pure water per the phase change principle.

Why the others are wrong:

• A: Disinfects but doesn't remove chemical impurities.
• B: Removes suspended solids only, not dissolved ones.
• D: Absorbs some organics but leaves inorganic salts.

Final answer: C