Soft and Hard Water

Q.

What is the chemical name of water?

1. Hydrogen trioxide

2. Hydrogen dioxide

3. Dihydrogen oxide

4. Hydrogen oxygen

Q.

Why hard water is unfit for drinking purpose

Q.

Is sodium hypochlorite safe for drinking water?

Q. Some substances when dissolved in water cause hardness of water.
a) Which of the following substances cause hardness of water? Sodium chloride, calcium bicarbonate, calcium sulphate, magnesium sulphate, calcium chloride, magnesium carbonate.
b) The hardness due to which of the above salts cannot be removed by boiling?

Q. Soap is not effective in hard water.

1. True
2. False

Q.

A water is said to be hard if:

1. It contains minerals.

2. It does not lather readily with soap.

3. It does not contain minerals.

4. It lathers readily with soap.

Q.

There are two water samples one in test-tube A and another in test-tube B. It was observed that water in both test-tubes A and B does not give lather with soap. However, after boiling the water in both the test-tubes A and B, the water in test-tube B does give lather with soap. Which among the following statements is correct?

1. Water in both the test-tubes is permanent hard water.

2. Water in test-tube A is permanent hard water while in test-tube B is temporary hard water.

3. Water in test-tube A is temporary hard water while in test-tube B is permanent hard water.

4. Water in both the test-tubes is temporary hard water.

Q.

Heavy water is a water molecule containing

1. It is used for removing permanant hardness of water.

2. It is used for manufacturing sodium compounds like borates.

3. It is used as a cleaning agent for domestic purposes.

4. All of the given options are correct