Hardness of Water and Treatment

Q.

What is the Zeolite softening process?

Q.

Explaine lux_flood concept of acid and base with example

Q.

Discuss the principle and method of softening of hard water by synthetic ion-exchange resins.

Q.

What are the methods used for softening hard water?

Q.

What is the cause of the permanent hardness of water?

Q.

What causes the temporary and permanent hardness of water?

Q. What is the degree of hardness of a sample of water containing $24\text{mg}$ of $MgS{O}_4$ (molecular mass $120$) per kg of water?

1. $10\text{ppm}$
2. $15\text{ppm}$
3. $20\text{ppm}$
4. $25\text{ppm}$

Q.

Why silver nitrate is called lunar caustic?

Q.

What is formula for permutit or zeolite which is used as softer in ion-exchange method?

Q. Calgon is used for water treatment. Which of the following statement is not true about Calgon?

1. It is also known as Graham's salt.
2. Calgon contains the $2^{nd}$
   most abundant element by weight in the Earth's crust.
3. It does not remove $C{a}^{2+}$ ion by precipitaion.
4. It is polymeric compound and is water soluble.

Q.

The crystals of sodium chloride produces a crackling sound on heating, called ______.

Q. Hard water when passed through ion - exchange resin containing RCOOH groups becomes free from:

1. $H_3{O}^{+}$ions
2. $C{a}^{2+}$ ions
3. $C{l}^{-}$ions
4. $S{O}_4^{2-}$ ions

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. Temporary hardness is due to bicarbonates of $M{g}^{2+}$ and $C{a}^{2+}$. It is removed by addition of CaO as follows: $Ca(HC{O}_3{)}_2+CaO\to 2CaC{O}_3+H_{2}O$ Mass of CaO required to precipitate $2gCaC{O}_3$

1. 2 g
2. 1.12 g
3. 0.56 g
4. 0.28 g

Q. The method used to remove temporary hardness of water is:

1. Calgon method
2. Clark's method
3. Ion-exchange method
4. Synthetic resins method

Q.

Water is cooled from $4°C$ to $0°C$. It will :

Q.

How are synthetic detergents better than soaps ?

Q. Which of the following will give maximum type of cations in water?(1) KCI.MgCl2.6H20(3) K, Fe(CN)(2) K.Fe(CN)(4) \lbrack Ag(CN)2

Q. Which of the following statements are correct regarding the hardness of water?

1. The temporary hardness of water is due to the presence of bicarbonates of $CaandMg$
2. The temporary hardness of water is due to the presence of sulphates of $NaandMg.$
3. The permanent hardness of water is due to the presence of bicarbonates of $NaandMg.$
4. Permanent hardness is due to presence of soluble chlorides and sulphates of $CaandMg.$

Q.

Chemical A is used for water softening to remove temporary hardness. A reacts with sodium carbonate to generate caustic soda. When $C{O}_2$ is bubbled through a solution of A, it turns cloudy. What is the chemical formula of A

1. 

2. 

3. CaO

4. 

Q. One of the following is an incorrect statement, point it out.

1. Permanent hardness can be removed by boiling water
2. Hardness of water effects soap consumption
3. Temporary hardnes is due to bicarbonates of Ca and Mg
4. Permanent hardness is due to the soluble $S{O}_4^{2-}C{l}^{-},N{O}_3^{-}$ of Ca and Mg

Q.

Why hard water is not suitable for washing clothes? Explain with equation

Q. The % of S in an organic compound whose 0.32g produces 0.233 g of BaSO4 is (Molar Mass of $BaS{O}_4$=233)

1. 23.5
2. 1
3. 10
4. 32.1

Q. When zeolite, which is hydrated sodium aluminium silicate, is treated with hard water the sodium ions are exchanged with

1. $H^{+}$ ions
2. $C{a}^{2+}$ ions
3. $M{g}^{2+}$ ions
4. (b) and (c) above.

Q.

Bithional is added to soaps to _______.

Q.

Can you use soaps and detergents to check the hardness of water ?

Q.

What is the name of the compound ${\left({\mathrm{NH}}_4\right)}_3{\mathrm{PO}}_4$?

Q.

Assertion (A): Temporary hardness of water can be removed by boiling.

Reason (R): Bicarbonates of calcium and magnesium undergo thermal decomposition.

1. Both A and R are true and R is the correct explanation of A.

2. Both A and R are true, but R is not the correct explanation of A.

3. A is true and R is false.

4. A is false and R is true.

Q.

Temporary hardness of water is removed in Clarks process by adding:

1. Lime

2. Borax

3. Calgon

4. Caustic soda

Q. Choose the correct statement regarding Calgon's process

1. Used for softening hard water
2. Calgon is trade name of sodium hexametaphosphate $(NaP{O}_3{)}_6$
3. Complex anion precipitate $M{g}^{+2}$ and $C{a}^{+2}$ from solution
4. $M{g}^{+2}$ and $C{a}^{+2}$ ions displaces $N{a}^{+}$ from complex anion.