Per NCERT, what is COAGULATION as a water-treatment technique?
ABoiling the water for an hour
BMixing salt with the water
CFreezing the water
DAdding a chemical (e.g. alum) that causes fine suspended particles to clump into larger flocs, which then settle and can be filtered out
Answer & Solution
Correct answer: D. Adding a chemical (e.g. alum) that causes fine suspended particles to clump into larger flocs, which then settle and can be filtered out
Per NCERT §5.4.3 B, coagulation with alum aggregates fine particles for easier removal. The other options misstate.
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