Softening of Hard Water

Q.

Soap forms insoluble precipitates with calcium and magnesium ions present in hard water.

1. True

2. False

Q. Assertion (A): Hardness of water is removed by treatment with sodium carbonate.
Reason (R): Sodium carbonate reacts with soluble magnesium and calcium chloride to form water soluble compounds.

1. (A) and (R) both are correct and (R) is the correct explanation of (A).
2. (A) and (R) both are correct but (R) is not the correct explanation of (A).
3. (A) is correct but (R) is not correct.
4. (A) is not correct but (R) is correct.

Q. Permanent hardness of water is due to the presence of chlorides and salts of calcium and magnesium. It can be removed by using .

1. caustic soda
2. washing soda
3. sulphates
4. bicarbonates

Q. Soap is not effective in hard water.

1. True
2. False

Q. Rahul took 25 ml of sea water in a beaker and added one spoon of sodium carbonate to it. Which of the following will he observe?

1. Precipitate is formed
2. Solution colour changes to blue
3. Bubbles are formed
4. Solution colour changes to red

Q. Temporary hardness of water is due to of calcium and magnesium and it can be removed by.

1. sedimentation
2. boiling
3. sulphates
4. bicarbonates

Q. The hardness of water is due to the presence of:

1. sodium and magnesium salts
2. calcium and sodium salts
3. calcium and magnesium salts
4. ammonium and sodium salts

Q. Assertion (A): Hard water gives easy lather with soap.
Reason (R): Salts of calcium and magnesium react with soap to form insoluble salts.

1. (A) and (R) both are correct and (R) is the correct explanation of (A).
2. (A) is correct but (R) is not correct.
3. (A) and (R) both are correct but (R) is not the correct explanation of (A).
4. (A) is not correct but (R) is correct.

Q. Soft water does not produce much lather.

1. False
2. True