Hard and Soft Water

Q.

What is tincal and write its formula?

Q.

What is the difference between a hydrate and an anhydrate compound?

Q.

Assertion (A): Permanent hardness of water is removed by treatment with washing soda.
Reason(R): Washing soda reacts with soluble magnesium and calcium sulphate to form water-soluble compounds.

1. (A) is correct but (R) is not correct.

2. (A) is not correct but (R) is correct.

3. (A) and (R) both are correct and (R) is the correct explanation of (A).

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

Q. What is formed when calcium chloride and sodium carbonate are mixed?

Q.

A water is said to be hard if:

1. It lathers readily with soap.

2. It does not lather readily with soap.

3. It does not contain minerals.

4. It contains minerals.

Q. Hard water does not produce lather with soap readily.

1. False
2. True

Q. How will you categorize water as hard water and soft water?(1 mark)

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

Q.

The hardness of water can be detected using ______.

1. electrolysis

2. litmus paper

3. lathering soap

4. thermometer

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

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

Q. Soap is not effective in hard water.

1. True
2. False

Q. Which among the following is/are the reasons why hard water is not used in industrial boilers?

1. It causes corrosion of the boiler.
2. The heating efficiency decreases.
3. They produce rich lather with soap.
4. It contains small amount of salts.

Q. Soft water does not produce much lather.

1. False
2. True

Q. The stone like deposit formed at the bottom of a boiler, when hard water is boiled into it, is called:

1. scaling
2. galvanising
3. rusting
4. lathering