250+ TOP MCQs on Inorganic Chemical – Water and Air and Answers

Chemical Industry Multiple Choice Questions on “Inorganic Chemical – Water and Air”.

1. Dissolved salts of Ca and Mg which types of water impurity?
a) Hardness impurity
b) Soluble colour compounds
c) Insoluble matter impurity
d) Pathogenic

Answer: a
Clarification: Ca and Mg bicarbonates are the hardness impurities of water and it can be reduced by boiling to precipitate insoluble carbonates, but from sediments. By chemical reaction or ion exchange also it can be removing.

2. In which types of conditioning process, synthetic resins are used?
a) Lime-soda process
b) Chlorination
c) Ion-exchange
d) Deodorization

Answer: c
Explanation; Synthetic resins are used for cation or anion exchange in ion-exchange process of conditioning process. Activated carbon adsorption is done in decolorization and deodorization.

3. Which one are the largest users of water by industry?
a) Steel
b) Miscellaneous
c) Processing
d) Power generation

Answer: a
Clarification: The largest users of water industry are-steel, oil refineries, pulp and paper. In processing, water is entering into or contacting manufactured products. Power generations, surface condensers and feed water.

4. Which raw material mentioned below is not required in lime soda process?
a) Quicklime
b) Light soda ash
c) Alum
d) Oil

Answer: d
Clarification: The three principal chemicals required for the lime-soda process are quicklime or hydrated lime, light soda ash contain (98% Na₂CO₃) and alum[Al₂(SO₄).xH₂O]. Small amount of activated carbon also required.

5. Which compound is added to the cation exchanger in back flow?
a) Weak acid
b) Strong acid
c) High basic solution
d) Low basic solution

Answer: b
Clarification: In ion-exchange process, when the exchange capacity of the resin has been exceeded, the activity of the ion exchange resin can be readily regenerated by forcing the reverse reaction to occur. Strong acid is added to the cation exchanger in back flow and highly basic solution is added to the anion exchange resin.

6. What is the distillation method of obtaining fresh water from saline waters?
a) Solvent extraction
b) Reverse osmosis
c) Vapor recompression
d) Hydrocarbon hydrates

Answer: c
Clarification: Evaporation or distillation method of obtaining fresh water from saline waters are-
Single stage flash, vapour recompression, multistage flash while freezing or crystallization process is indirect refrigeration and hydrocarbon hydrates.

7. Why moderators are used in nuclear process?
a) To absorption of neutrons
b) To increase the reaction rate
c) To provide collision
d) To increase the temperature

Answer: a
Clarification: Moderating materials are required if the absorption of neutrons is to take place at or near the environmental temperature of the reactor. The fission neutrons liberated are extremely high energy and must be moderated to environment temperature by non-absorption type collision with moderating materials.

8. What is the disadvantage of vapour compression?
a) Less no of evaporator
b) Less energy requirements
c) High pressure steam
d) Use of inert

Answer: c
Clarification: Disadvantages of vapour compression are high priced energy in the form of electricity or high pressure steam is needed for operating the compressor.

9. Which cost is mainly appear in producing freshwater from seawater?
a) Capital cost
b) Operating cost
c) Optimum cost
d) Energy cost

Answer: d
Clarification: The two main costs in producing freshwater from seawater are – energy costs, fixed charges on investment. These are closely related in an economic balance. If one tries to reduce energy cost, the investment costs are invariably increased.

10. Which component is responsible for killing bacteria in water?
a) Low concentration of OH-
b) High concentration of OH-
c) High concentration of acid
d) Low concentration of acid

Answer: b
Clarification: Because of the higher concentration of hydroxide ion maintained to kill bacteria and insure a reasonable removal of Mg as Mg(OH)₂, this effluent water must be re-carbonated to neutralize the excess alkalinity.