Same chapter3 marksDifficulty: Medium
What is heavy water, and state two of its uses.
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3 marksDifficulty: Medium
What is hard water? Distinguish between temporary and permanent hardness and state how each is removed.
Original Khojo Papers practice question — not from a past board paper.
Answer
Hard water contains dissolved salts of calcium and magnesium that prevent soap from lathering readily. Temporary hardness is due to the bicarbonates and is removed by boiling or by adding slaked lime. Permanent hardness is due to the chlorides and sulphates and is removed by washing soda or by ion exchange.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
Both kinds are removed together by an ion-exchange resin or by distillation.
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