250+ TOP MCQs on Ion Exchange Process and Answers

Waste Water Engineering Multiple Choice Questions on “Ion Exchange Process”.

1. Ion exchange units are known as ______
a) Water hardeners
b) Water softeners
c) Water purifiers
d) Exchangers
Answer: b
Clarification: Ion exchange units that replace calcium and magnesium ions from water are known as water softeners. They may also remove varying amounts of other inorganic pollutants such as metals.

2. Water softener units work most efficiently with particulate water.
a) True
b) False
Answer: b
Clarification: Water softener units work most efficiently with particulate-free water. Ion exchange units that replace calcium and magnesium ions from water are known as water softeners.

3. Which of these have a negative electrical charge?
a) Calcium
b) Magnesium
c) Sodium
d) Chloride
Answer: d
Clarification: Calcium and magnesium ions are atoms having a positive electrical charge, as do sodium and potassium ions. Ions of the same charge can be exchanged.

4. The ions with opposite charge can be exchanged.
a) True
b) False
Answer: b
Clarification: Ions of the same charge can be exchanged. In the process, the water containing calcium and magnesium ions is considered and substance containing sodium or potassium ions is used against it.

5. While designing the demineralisation plant what is considered as the weak acidic cation load?
a) Alkaline hardness
b) Alkaline hardness+ EMA
c) EMA
d) Silica
Answer: a
Clarification: The load for Weak acid cation is alkaline hardness alone. Alkalinity is expressed as phenolphthalein alkalinity. It is also expressed as methyl orange alkalinity.

6. While designing the demineralisation plant what is considered as the strong acidic cation load?
a) Alkaline hardness
b) Alkaline hardness + EMA
c) EMA
d) Silica
Answer: b
Clarification: The load for Weak acid cation is alkaline hardness alone. This is also equivalent to total anions. Total anions is equivalent to alkaline hardness + EMA.

7. While designing the demineralisation plant what is considered as the strong basic anion load?
a) Alkaline hardness
b) Alkaline hardness + EMA+CO₂
c) EMA+Silica
d) Silica+CO₂+ Alkalinity+EMA
Answer: d
Clarification: The load for strong basic anion is Silica+CO₂+ Alkalinity+EMA. This is in the case where there is no degasser.
In case there is a degasser then the CO₂ load is not considered.

8. While designing the demineralisation plant what is considered as the weak basic anion load?
a) Alkaline hardness
b) Alkaline hardness + EMA
c) EMA
d) Silica
Answer: c
Clarification: The load for weak basic anion is EMA alone. EMA constitutes of chlorides, sulphides, nitrates etc. It is the sum total of these ions.

9. When is strong basic anion not necessary?
a) Silica is nil
b) CO₂ is nil
c) Fluroine is nil
d) Sulphate is nil
Answer: a
Clarification: When silica is nil, there is no requirement of a strong basic anion. Degasser removes CO₂. A degasser tower is used in such cases.

10. When the hardness and alkalinity are around 30% what should be used?
a) SAC
b) WAC
c) WAC, SAC
d) WAC, SAC, WBA
Answer: c
Clarification: When the hardness and alkalinity are around 30%, then WAC and SAC should be used. WAC removes temporary hardness caused by alkalinity. SAC removes EMA and alkalinity.

11. In case along with silica, there is high content in sulphide and chloride what should be used?
a) WBA
b) WBA and SBA
c) SBA
d) SBA,WBA and WAC
Answer: b
Clarification: In case the sulphide and chloride are present then WBA should be used. SBA removes only silica and alkalinity. It doesn’t remove EMA.

12. What is the preferred regenerant in case of cation exchanger?
a) HCl
b) H₂SO₄
c) H₂CO₃
d) HF
Answer: a
Clarification: The preffered regenerant in case of cation exchanger is HCl. Regeneration is a process necessary to regenerate the resin. In this way the resin can be reused for the next demineralization process.

13. What is the preferred regenerant in case of anion exchanger?
a) NaCl
b) NaOH
c) Na₂SO₄
d) Na₂CO₃
Answer: b
Clarification: The preffered regenerant in case of anion exchanger is NaOH. Regeneration is a process necessary to regenerate the resin. In this way the resin can be reused for the next demineralization process.

14. For obtaining Silica<5 ppm which of these should be utilized?
a) SBA followed by Mixed be
b) SBA
c) WBA SBA followed by mixed bed
d) Mixed bed
Answer: a
Clarification: A mixed bed is usually followed after a SBA to obtain silica level < 5 ppm. Mixed bed constitutes both an anion and cation exchanger. To obtain stringent level of silica mixed bed should be implemented.