Permanent Hardness

Q.

Which ion does not cause hardness in water?

1. Calcium

2. Magnesium

3. Sodium

4. Iron

Q. Calcium hydroxide is used to remove temporary hardness of water.

1. True
2. False

Q.

Permanent hardness of water cannot be removed by _______?

1. Boiling

2. Permutit method

3. Ion exchange method

4. Washing soda method

Q.

The permanent hardness of water cannot be removed by boiling. Why?

Q.

Choose the odd one out. Give reasons for the choice.

Magnesium sulphate, calcium sulphate, magnesium chloride, magnesium bicarbonate.

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 insoluble compounds.

1. Statements (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) and (R) both are false

Q.

A hydrated solid X on heating initially gives a monohydrated compound Y. Y upon heating above 373 leads to an anhydrous white powder Z. X and Z, respectively, are:

1. Baking soda and dead burnt plaster.

2. Washing soda and soda ash

3. Washing soda and dead burnt plaster.

4. Baking soda and soda ash

Q. Washing soda is used for treating .

1. temporary hardness
2. permanent hardness
3. soft water

Q.

What are the causes of the permanent hardness of water?

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

Q.

_________________easily forms rich lather with soap.

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

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

Q.

Salts while crystallising out from their aqueous solution, unite with a definite quantity of water which is known as _________ .

1. water of crystallization

2. Efflorescence

3. Deliquescence

4. anomalous behavior

Q. What is the permanent hardness of water? How can it be removed? [2 Marks]

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.

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

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

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

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

Q. What is permanent hardness of water?

Q.

Permanent hardness of water can be removed by adding ____.

1. Sodium carbonate

2. Sodium bicarbonate

3. Calcium sulphate

4. Sodium chloride

Q.

What is the permanent hardness of water? How can it be removed?

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

Q.

What are the causes of the permanent hardness of water?

Q. Which of the following processes will produce hard water?

Q.

Define soft and hard water.

Q. Which instrument is used to measure a specific volume of liquid?

1. Pipette
2. Manometer
3. Calorimeter
4. Balance

Q.

6. A divalent salt X, which contributes to hardness of water, combines with washing soda and insoluble salt Y and common salt. Salt Y is also used for the laboratory preparation of CO_2. Identify X and Y, respectively.

1. CaSO₄ , CaCO₃

2. MgSO₄ , MgCO₃

3. CaCl₂ , CaCO3

4. MgCl_{2 ,} MgCO₃

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) 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.

What is the permanent hardness of water? How can it be removed?

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

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

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

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

Q.

A saturated solution is the solution in which

1. No more amount of substances can be added

2. None of the given options

3. More substances can be added to the solution on heating

4. Adding of substance depends upon solution

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