Water Treatment MCQ
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Multiple Choice Questions (MCQ) on Fuels
multiple-choice Questions
Q.1. The purest form of natural water is
- River water
- Sea water
- Underground water
- Rain water
Answer: Rain water
Q.2. The alkaline hardness of water is due to the presence of the following salts of calcium and magnesium in water.
- HCO3− only
- HCO3− and CO32− only
- SO42− only
- HCO3− , CO32− , and OH− only
Answer: HCO3− , CO32− , and OH− only
Q.3. A sample of water contains 120 mg of Mg2+ per liter. The hardness of the sample of water in terms of CaCO3 equivalent is
- 120 mg/L
- 500 mg/L
- 250 mg/L
- 1000 mg/L
Answer: 500 mg/L
Q.4. The total hardness of a sample of water is 1.88°Cl eq. CaCO3 . Its hardness in ppm would be
- 26.88
- 18.8
- 0.188
- 34.65
Answer: 26.88
Q.5. The color obtained by adding EBT indicator to a sample of water containing Ca2+ and Mg2+ at pH = 9–10 is
- Blue
- Wine red
- Pink
- No colour
Answer: Wine red
Q.6. On boiling and filtering hard water, water sample contains
- Temporary hardness
- Permanent hardness
- Both
- None of the above
Answer: Permanent hardness
Q.7. The blow-down operation causes the removal of
- Scales
- Sludges
- Acidity
- Basicity
Answer: Sludges
Q.8. Scale formation in boiler-feed water is due to
- Metallic deposition
- Corrosion in boilers
- Deposition of hard water
- All the above
Answer: Deposition of hard water
Q.9. Scale formation is mainly due to which of the following salt present in boiler-feed water?
- CaSO4
- MgCO3
- Na2 SO4
- KCl
Answer: CaSO4
Q.10. Solubility of CaSO4 salt present in water
- Increases with increase in temperature
- Decreases with increase in temperature
- Remain unchanged with increase in temperature
- Not having any defi nite change with increase in temperature.
Answer: Decreases with increase in temperature
Q.11. EDTA method is used for determining
- Temporary hardness
- Permanent hardness
- Temporary and permanent hardness
- Alkalinity
Answer: Temporary and permanent hardness
Q.12. When phenolphthalein alkalinity, P = M then alkalinity is due to
- OH−
- CO32−
- HCO3−
- CO32− and HCO3−
Answer: CO32−
Q.13. The permanent hardness of water cannot be removed by
- Lime soda process
- Permutit process
- Boiling
- Demineralization process
Answer: Boiling
Q.14. Permutit is chemically
- Sodium silicate
- Hydrated sodium alumino silicate
- Aluminium silicate
- All the above
Answer: Hydrated sodium aluminosilicate
Q.15. Hard water is not suitable for use in boilers because
- It has a higher boiling point
- It leads to scale formation in the boiler
- It consumes more fuel in steam generation
- The quality of steam generated is not good
Answer: It leads to scale formation in the boiler
Q.16. Which of the following substances is capable of removing dissolved oxygen from water?
- Cl2
- N2 H4
- Na2 SO4
- CaOCl2
Answer: N2 H4
Q.17. Sterilization of water can be done by using
- H2 O2
- O2
- Cl2
- NaOH
Answer: Cl2
Q.18. Coagulants help in settling of
- Suspended impurities only
- Finely suspended impurities only
- Colloidal particles only
- Both the suspended and colloidal particles
Answer: Both the suspended and colloidal particles
Q.19. 1 ppm of K+ present in a sample of demineralized water is equal to
- 4.3478 × 10– 8 mol L–1
- 2.564 × 10– 10 mol L–1
- 2.564 × 10– 5 mol L–1
- None of the above
Answer: 2.564 × 10– 5 mol L–1
Q.20. Calgon is a name given to
- Sodium silicate
- Sodium hexameta phosphate
- Sodium meta phosphate
- Calcium phosphate
Answer: Sodium hexameta phosphate
Q.21. Permutit exchanges Ca2+ and Mg2+ ions present in hard water with
- Zeolite ions
- H + ions
- Na + ions
- None of these
Answer: Na + ions
Q.22. The exhausted zeolite can be regenerated by treating it with
- 10% NaCl solution
- 50% NaCl solution
- 10% HCl solution
- 50% HCl solution
Answer: 10% NaCl solution
Q.23. Brackish water contains dissolved
- CaSO4
- MgCl2
- NaCl
- Na2 SO4
Answer: MgCl2
Q.24. Which of the following samples of water cannot be softened by zeolite process?
- Water containing temporary hardness
- Water containing permanent hardness
- Water containing excess of alkalinity
- Water containing excess of dissolved salts
Answer: Water containing excess of alkalinity
Q.25. The cation-exchange resins possess
- Acidic groups
- Basic groups
- Amphoteric groups
- None of these
Answer: Acidic groups
Q.26. Priming and foaming process in boiler-feed water is due to
- The formation of air bubbles and production of wet steam
- The formation of scales
- The formation of sludges
- None of these
Answer: The formation of air bubbles and production of wet steam
Q.27. The cation and anion resins are made up of the basic polymer unit of
- Polyvinyl chloride
- Poly acrylate
- Poly styrene
- Polybutadiene
Answer: Poly acrylate
Q.28. By ion-exchange process the hardness of water can be reduced up to
- 0 ppm
- 5 ppm
- 10 ppm
- 15 ppm
Answer: 0 ppm
Q.29. Boiler corrosion caused by using highly alkaline water in boiler is called
- Corrosion
- Boiler corrosion
- Caustic embrittlement
- Erosion
Answer: Caustic embrittlement
Q.30. Desalination is the process of removing
- Common salt from sea water and making it potable
- Hard salts from sea water
- NaOH from hard water
- None of the above
Answer: Common salt from sea water and making it potable
Q.31. An exhausted anion-exchange resin can be regenerated by treating it with
- Conc. HCl solution
- Conc. NaOH solution
- Dilute brine solution
- Conc. brine solution
Answer: Conc. NaOH solution
Q.32. Tannins and agar-agar are used for
- Phosphate conditioning
- Colloidal conditioning
- Radioactive conditioning
- Calgon conditioning
Answer: Colloidal conditioning
Q.33. Alum is commonly used in the treatment of municipal water for
- Filteration
- Sedimentation
- Coagulation
- Flocculant
Answer: Flocculant
Q.34. The chemical formula of alum is
- K2 SO4 . Al2 (SO4)3 . 20H2O
- KNO3 . Al2 (SO4)3 . 24 H2O
- K2 SO4 . Al2 (SO4)3 . 24 H2O
- K2 SO4 . Al2 (SO4)3 . 21 H2O
Answer: K2 SO4 . Al2 (SO4)3 . 24 H2O
Q.35. Liquid chlorine is most effective
- Disinfectant
- Coagulant
- Flocculant
- Sterilizing agent
Answer: Disinfectant
Q.36. The soft, loose, and slimy precipitate formed within the boiler is called
- Scale
- Sludge
- Flocculant
- Coagulant
Answer: Sludge
Q.37. In reverse osmosis (RO) the flow of solvent is due to
- Potential gradient
- Vapour pressure gradient
- Concentration gradient
- None of the above
Answer: Concentration gradient
Q.38. In the RO process, the membrane used is
- Polysulfone
- Polysulfone amide
- Poly amide
- All above
Answer: All above
Q.39. The chemical formula of bleaching powder is
- Cl2
- HOCl
- NH2Cl
- CaOCl2
Answer: CaOCl2
Q.40. The acid responsible for the disinfection of germs and bacteria is
- HCl
- HNO3
- HOCl
- H2 CO3
Answer: HOCl
Q.41. The amount of water available for human consumption is
- 1%
- 3%
- 97%
- 5%
Answer: 1%
Q.42. Water causes weathering of rocks due to the following phenomenon
- Dissolution
- Hydration
- Hydrolysis
- All of the above
Answer: All of the above
Q.43. The hardness of water is due to
- K and Na salts
- Salts of iron
- Salts of Ca and Mg
- SiO2
Answer: Salts of Ca and Mg
Q.44. Permanent hardness is due to
- Carbonate of Ca
- Bicarbonate of Mg
- Chloride and sulphates of Ca and Mg
- None of the above
Answer: Chloride and sulphates of Ca and Mg
Q.45. The most commonly used unit to express hardness is
- Degree French
- Degree Clarke
- ppm
- grains /gallon
Answer: ppm
Q.46. Scale in boilers are formed due to
- Deposition of CaCO3
- Deposition of CaSO4
- Hydrolysis of magnesium salts
- All of the above
Answer: All of the above
Q.47. Excess nitrate in drinking water causes
- Anaemia
- Blue baby syndrome
- Irritation in skin
- Mouth blisters
Answer: Blue baby syndrome
Q.48. The maximum permissible limit of fluoride in drinking water is
- 1.5 ppm
- 5 ppm
- 3 ppm
- 8 ppm
Answer: 1.5 ppm
Q.49. The Lime soda process uses
- Ca(OH)2
- Na2CO3
- Both the above
- None of the above
Answer: Both the above
Q.50. Which process is not used for the desalination of water
- Reverse osmosis
- Lime soda process
- Electrodialysis
- Flash evaporation
Answer: Lime soda process
Q.51. Residual hardness in the ion exchange process is
- 10-15 ppm
- 30-60 ppm
- 0-2 ppm
- 15-30 ppm
Answer: 0-2 ppm
Q.52. Alkalinity in water is due to
- OH–
- CO32–
- HCO3–
- All of the above
Answer: All of the above
Q.53. Which is not used for disinfection of water
- Chlorination
- Electrodialysis
- Ozonisation
- Addition of KMnO4
Answer: Electrodialysis
Q.54. Dissolved oxygen in water is determined by
- Mohr’s method
- Gravimetric method
- Winklers method or iodometric titration
- EDTA method
Answer: Winklers method or iodometric titration
Q.55. Flash evaporation is a method of getting pure water from
- Sea water
- Industrial waste water
- Domestic sewage
- River water
Answer: Sea water
Q.56. Disinfection of water removes
- Salts from water
- Pathogenic bacteria from water
- Dissolved oxygen from water
- Hardness from water
Answer: Pathogenic bacteria from water
Q.57. The acceptable pH range for drinking water is
- 7 to 8.5
- 6 to 7
- 6.5 to 9.2
- 8 to 10
Answer: 7 to 8.5
Q.58. Which of the following is removed from water using the Nalgonda technique
- Chlorine
- Fluorine
- Sulphates
- Hardness in water
Answer: Fluorine
Q.59. The organic impurities from sewage are removed by
- Preliminary treatment
- Primary treatment
- Secondary treatment
- Tertiary treatment
Answer: Secondary treatment