The temporary hardness of water is due to
- (A)
- (B)NaCl
- (C)✓ Correct
- (D)
Answer: (C)
Solution
Temporary hardness is the kind you can boil away, and it comes from dissolved calcium (and magnesium) bicarbonate, . Heating decomposes it, , dropping the hardness out as insoluble carbonate. Chlorides and sulphates give permanent hardness, which boiling does not remove.
JEE Main · 2019 · 09 Jan 2019 · Shift 2 · Single correct option