Single correct option
Consider the following statements about hardness of water.
1. Temporary hardness is caused by the bicarbonates of calcium and magnesium.
2. Permanent hardness can be removed simply by boiling the water.
Which of the statements given above is/are correct?
1. Temporary hardness is caused by the bicarbonates of calcium and magnesium.
2. Permanent hardness can be removed simply by boiling the water.
Which of the statements given above is/are correct?
- A. 1 only
- B. 2 only
- C. Both 1 and 2
- D. Neither 1 nor 2
Show answer and solution
Answer: (A) 1 only
Temporary hardness arises from dissolved calcium and magnesium bicarbonates, and boiling decomposes them into insoluble carbonates, so statement 1 is correct. Permanent hardness is due to chlorides and sulphates of calcium and magnesium, which do not precipitate on boiling and need washing soda or ion exchange. So statement 2 is wrong.
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