Temporary Hardness and Removal

Q. The reagent(s) used for softening the temporary hardness of water is (are):

1. $C{a}_3(P{O}_4{)}_2$
2. $Ca(OH{)}_2$
3. $N{a}_{2}C{O}_3$
4. $NaOCl$

Q.

The temporary hardness of water can be removed by Clark's Method using _____.

1. 

2. 

3. 

4. 

Q.

Which of the following can be used to remove temporary hardness of water?

1. Nitrolim

2. Hydrolith

3. Plaster of Paris

4. Slaked Lime

Q.

Which of the following is a suitable method of removing hardness from water?

1. Boiling
2. Adding washing soda
3. Ion- exchange
4. Adding sodium chloride

Q.

Temporary hardness of water is due to the presence of

1. Magnesium sulphate
2. Calcium chloride
3. Magnesium bicarbonate
4. Calcium carbonate

Q.

In this Ca SO₄.1/2 (H₂O ) how a molecule of water can be divide into half?

Q. (a) Name a sodium compound used for softening hard water.
(b) Which compound of calcium is used for disinfecting drinking water supply?
(c) Name a metal compound which has detergent properties (cleansing properties).
(d) Name one compound of calcium which is used for removing the colour of a coloured cloth.
(e) State a peculiar (or remarkable) property of plaster of Paris.
(f) Name the substance obtained by the action of chlorine on solid (dry) slaked lime.

Q. Temporary hardness of water can be removed by Clark's Method using:

1. $Ca(OH{)}_2$
2. $N{a}_{2}C{O}_3$
3. $NaOH$
4. $NaCl$

Q. Water becomes useless for drinking purpose if the fluoride ion concentration exceeds :

1. 20 ppm
2. 50 ppm
3. 2-4 ppm
4. 10 ppm

Q.

Hard water gives a rich lather with soap.

1. True
2. False

Q.

Temporary hardness of water is due to the presence of

1. Calcium carbonate

2. Magnesium bicarbonate

3. Magnesium sulphate

4. Calcium chloride

Q.

The reaction involved in the removal of temporary hardness of water is:

1. $\text{Ca}({\text{HCO}}_3$)${}_2$ $\stackrel{\text{Heat}}{\to }$ ${\text{CaCO}}_3+{\text{H}}_2\text{O}+{\text{CO}}_2\uparrow$

2. ${\text{CaCl}}_2+{\text{Na}}_2{\text{CO}}_3$ $\to$ ${\text{CaCO}}_3(\downarrow )+2\text{NaCl}$
3. ${\text{MgSO}}_4+$ ${\text{Na}}_2{\text{Al}}_2{\text{Si}}_2{\text{O}}_8.{\text{xH}}_2\text{O}$ $\to$ ${\text{MgAl}}_2{\text{Si}}_2{\text{O}}_8.{\text{xH}}_2\text{O}+{\text{Na}}_2{\text{SO}}_4$
4. ${\text{2CaCl}}_2+({\text{NaPO}}_3$)${}_6$ $\to$ ${\text{Na}}_2[{\text{Ca}}_2{\text{PO}}_3$)${}_6$] + $\text{4NaCl}$

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.

Which of the following is a suitable method of removing hardness from water?

1. Boiling
2. Adding washing soda
3. Ion- exchange
4. Adding sodium chloride

Q.

Give the reasons for the following statement.

Temporary hardness can be removed by boiling.