McqMate
These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Uncategorized topics .
| 1. |
Hardness of water is due to the presence of salts of |
| A. | potassium |
| B. | chlorine |
| C. | magnesium |
| D. | boron |
| Answer» C. magnesium | |
| Explanation: hardness of water is due to the presence of salts of calcium and magnesium. hard drinking water may have moderate health benefits, but can pose serious problems in industrial settings, where water hardness is monitored to avoid costly breakdowns in boilers, cooling towers, and other equipment that handles water. | |
| 2. |
Select the incorrect statement from the following option. |
| A. | water which does not form lather with soap and forms white scum is called hard water |
| B. | hard water contains dissolved calcium and magnesium salts in it |
| C. | in hard water, cleansing quality of soap is depressed |
| D. | due to the presence of dissolved hardness- producing salts, the boiling point of water is depressed |
| Answer» D. due to the presence of dissolved hardness- producing salts, the boiling point of water is depressed | |
| Explanation: due to the presence of dissolved hardness-producing salts, the boiling point of water is elevated. elevation in boiling point is one of the most important colligative property. all the other options are correct. | |
| 3. |
Select the incorrect statement from the following option. |
| A. | the taste of hard water is better than soft water |
| B. | the dissolved calcium in hard water can help to produce strong teeth |
| C. | hard water coats the lead piping with a layer of insoluble calcium carbonate which prevents poisonous lead dissolving in water |
| D. | boiler feed water should also be hard in nature |
| Answer» D. boiler feed water should also be hard in nature | |
| Explanation: boiler feed water should be free from hardness otherwise explosion may occur. all the other options are correct. the taste of hard water is better than soft water and dissolved calcium in hard water can help to produce strong teeth. hard water coats the | |
| 4. |
Which of the following is not a unit of hardness? |
| A. | parts per million |
| B. | degree centigrade |
| C. | degree clarke |
| D. | degree french |
| Answer» B. degree centigrade | |
| Explanation: degree centigrade is not a unit of hardness. degree centigrade is the unit of temperature. the unit for hardness is ppm (parts per million), degree clarke and degree french. all these three units are inter-related. | |
| 5. |
Hardness of water is conventionally expressed in terms of equivalent amount of |
| A. | h2co3 |
| B. | mgco3 |
| C. | caco3 |
| D. | na2 co3 |
| Answer» C. caco3 | |
| Explanation: hardness of water is conventionally expressed in terms of equivalent amount of caco3. the total water hardness is the sum of the molar concentrations of ca2+ and mg2+, in mol/l or mmol/l units. | |
| 6. |
The chemical equivalent of MgSO4 salt is |
| A. | 10,000 |
| B. | 30,000 |
| C. | 50,000 |
| D. | 70,000 |
| Answer» D. 70,000 | |
| Explanation: 1 degree clarke = 1 part of caco3 per 70,000 parts of water. it is calculated mathematically. | |
| 7. |
1 ppm = |
| A. | 0.07 0fr |
| B. | 0.70fr |
| C. | 0.10fr |
| D. | 0.010fr |
| Answer» C. 0.10fr | |
| Explanation: 1 ppm = 0.10fr. it is calculated mathematically. | |
| 8. |
How many grams of MgCO3 dissolved per litre gives 84 ppm hardness? |
| A. | 70.56 mg/l |
| B. | 48.23 mg/l |
| C. | 81.49mg/l |
| D. | 66.12 mg/l |
| Answer» A. 70.56 mg/l | |
| Explanation: 70.56 mg/l of mgco3 dissolved per litre gives 84 ppm hardness. | |
| 9. |
EDTA method for hardness determination is a less accurate and inconvenient procedure. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: edta method for hardness determination is a more accurate, convenient and rapid procedure. ethylene diaminetetraacetic acid (edta), is an amino poly-carboxylic acid and a colorless, water- soluble solid. | |
| 10. |
Estimation of hardness can be determined by types. |
| A. | 2 |
| B. | 3 |
| C. | 4 |
| D. | 5 |
| Answer» A. 2 | |
| Explanation: estimation of hardness can be determined by two types. they are soap titration method and edta method. | |
| 11. |
Total hardness of water can be determined by titrating the fixed volume of water against the standard solution. |
| A. | soap |
| B. | alkaline soap |
| C. | acidic soap |
| D. | alcoholic soap |
| Answer» D. alcoholic soap | |
| Explanation: total hardness of water can be determined by titrating the fixed volume of water against the standard alcoholic soap solution. | |
| 12. |
The sodium soap will precipitate all the hardness causing ions into their respective |
| A. | carbonates |
| B. | bicarbonates |
| C. | stereates |
| D. | chlorides |
| Answer» C. stereates | |
| Explanation: the sodium soap will precipitate all the hardness causing ions into their respective stereates in the beginning of the soap titration method. | |
| 13. |
The water which form lather directly with the soap is called |
| A. | hard water |
| B. | soft water |
| C. | partially hard water |
| D. | very hard water |
| Answer» B. soft water | |
| Explanation: the water which forms lather directly with the soap is called soft water. the water which forms precipitates when reacted with soap is called as the hard water. | |
| 14. |
EDTA method is also called as |
| A. | complexometric titration |
| B. | complex titration |
| C. | complement titration |
| D. | complexion titration |
| Answer» A. complexometric titration | |
| Explanation: edta method is also called as the complexometric titration. in edta method is ethylene diamine tetra acetate is the compound used to remove the hardness. | |
| 15. |
The indicator used in the EDTA method is |
| A. | benzene |
| B. | phenopthalene |
| C. | ethylene diamine |
| D. | erichrome black t |
| Answer» D. erichrome black t | |
| Explanation: the indicator used in the edta method is erichrome black t. the hardness causing ions like ca++ and mg++ forms the unstable complexes with reacting the erichrome black t. | |
| 16. |
The change in colour is sharper at the PH of |
| A. | 5 |
| B. | 10 |
| C. | 15 |
| D. | 20 |
| Answer» B. 10 | |
| Explanation: the change in the colour of the ions is sharper at the ph of the 10 than that of the other ranges of the ph. | |
| 17. |
At PH=10, the metal dye complex has the colour |
| A. | wine red |
| B. | blue |
| C. | green |
| D. | pink |
| Answer» A. wine red | |
| Explanation: at the ph=10, the metal dye complex ion has the colour is wine red but the dye itself has the blue colour at the ph of 10. | |
| 18. |
To prepare EDTA solution grams of EDTA is dissolved in the one litre of water. |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» D. 4 | |
| Explanation: to prepare edta solution, four grams of the edta is dissolved in the one litre of the water. this is the standard edta solution used to determine the hardness of water. | |
| 19. |
drops of indicator is used in the EDTA method. |
| A. | 1 to 2 drops |
| B. | 2 to 3 drops |
| C. | 2 to 4 drops |
| D. | 5 to 8 drops |
| Answer» A. 1 to 2 drops | |
| Explanation: 1 to 2 drops of the indicator is used in the edta method. 0.5gms of the dye is dissolved into the 100ml of alcohol and the indicator of two to three drops is added. | |
| 20. |
The buffer used in the EDTA solution must have the PH of |
| A. | 20 |
| B. | 15 |
| C. | 10 |
| D. | 5 |
| Answer» C. 10 | |
| Explanation: the buffer used in the edta solution must have the ph of 10. freshly prepared solutions are more affective to have the accurate results. | |
| 21. |
The standard hard water is prepared such that each ml must contain mg of CaCO3. |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» A. 1 | |
| Explanation: the 1g of pure caco3 is dissolved in the minimum amount of concentrated hcl diluted to 1ltr of distilled water such that it contains 1mg of caco3. | |
| 22. |
Water is mainly used in boilers for the generation of |
| A. | power |
| B. | electricity |
| C. | steam |
| D. | current |
| Answer» C. steam | |
| Explanation: water is mainly used in boilers for the generation of steam. this steam is further used in the power plants for the generation of electricity. | |
| 23. |
Which of the following is not a result of the excess of impurity in boiler-feed? |
| A. | scale and sludge formation |
| B. | decomposition |
| C. | corrosion, priming and foaming |
| D. | caustic embrittlement |
| Answer» B. decomposition | |
| Explanation: excess of impurities in boiler- feed results in scale and sludge formation, corrosion, priming, foaming and caustic embrittlement. it does not contribute to the decomposition process. | |
| 24. |
The scales decrease the efficiency of boiler and chances of explosions are also there. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: the scales decrease the efficiency of boiler and chances of explosions are also there. scale is the precipitate that is hard and adhering on the inner wall. | |
| 25. |
Foaming is caused by the formation of |
| A. | acids |
| B. | alcohols |
| C. | oils and alkalis |
| D. | ketones |
| Answer» C. oils and alkalis | |
| Explanation: foaming is caused by the formation of oils and alkalis. oils and alkalis becomes sticky and greasy on the surface and hence results in foaming. | |
| 26. |
Corrosion is the decay or disintegration of boiler body material either due to chemical or electrochemical reaction with environment. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: corrosion is the decay or disintegration of boiler body material either due to chemical or electrochemical reaction with environment. it converts a refined metal to a more stable form, such as its oxide, hydroxide, or sulphide. | |
| 27. |
Ion exchange process is also called as |
| A. | permutit’s process |
| B. | demineralization |
| C. | zeolite process |
| D. | lime soda process |
| Answer» B. demineralization | |
| Explanation: ion exchange process is also called as the demineralization. the zeolite process is otherwise called as the ion exchange process. | |
| 28. |
The operational cost of the ion exchange process is |
| A. | high |
| B. | low |
| C. | very high |
| D. | very low |
| Answer» B. low | |
| Explanation: the capital cost of the ion exchange process is very high. the operational cost of the ion exchange process is about low. | |
| 29. |
The hardness in the ion exchange process is reduced to |
| A. | 0-1ppm |
| B. | 0-2ppm |
| C. | 0-3ppm |
| D. | 0-4ppm |
| Answer» B. 0-2ppm | |
| Explanation: the hardness of the ion exchange process is reduced to 0 to 2ppm. it | |
| 30. |
The total are removed completely in the ion exchange process. |
| A. | dissolved gases |
| B. | dissolved solids |
| C. | dissolved solvents |
| D. | dissolved other impurities |
| Answer» B. dissolved solids | |
| Explanation: the total dissolved solids are removed completely in the ion exchange process. in lime soda process, the total dissolved solids are reduced only. | |
| 31. |
In ion exchange process, the iron and manganese ions are removed from the water. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: in ion exchange process, not only iron and manganese ions are removed from the water but also all the cations are removed. | |
| 32. |
Water softened during method will be ideal in boilers. |
| A. | zeolite method |
| B. | lime soda method |
| C. | demineralisation method |
| D. | permutit’s process |
| Answer» B. lime soda method | |
| Explanation: water softened during the demineralisation method is completely free from all the impurities and flaws. so, the water after the softening by this method will be ideal for boilers. | |
| 33. |
The regeneration of acids and alkalis in ion exchange process is |
| A. | cheaper |
| B. | costlier |
| C. | time taking |
| D. | hard process |
| Answer» B. costlier | |
| Explanation: the one of the disadvantages of the ion exchange process is the regeneration of the acids and alkalis in ion exchange process is costlier. | |
| 34. |
In ion exchange process, the cation exchange resin is generated by passing |
| A. | acids |
| B. | dilute acids |
| C. | alkalis |
| D. | dilute alkalis |
| Answer» B. dilute acids | |
| Explanation: in ion exchange process, the cation exchange resin is generated by passing the dilute acids. the anion exchange resin is generated by passing alkali. | |
| 35. |
In the case of the zeolites, ion exchange process do not function properly because of the |
| A. | turbidity |
| B. | suspended matter |
| C. | turbidity and suspended matter |
| D. | neither turbidity nor suspended matter |
| Answer» C. turbidity and suspended matter | |
| Explanation: in case of zeolites, ion exchange process do not function properly because of the turbidity and suspended matter as they send to cover the surface of the resin. | |
| 36. |
The initial equipment in the ion exchange process is |
| A. | more |
| B. | less |
| C. | very less |
| D. | very high |
| Answer» A. more | |
| Explanation: the initial equipment in the ion exchange process is more. continuous supply of softened water can be made available by providing storage facilities. | |
| 37. |
The residual hardness after the treatment of water is about |
| A. | 1 ppm |
| B. | less than 1ppm |
| C. | 2 ppm |
| D. | less than 2pmm |
| Answer» D. less than 2pmm | |
| Explanation: the residual hardness after the treatment of the water is about less than 2ppm. so, they are suitable for the high pressure boilers. | |
| 38. |
The continuous supply of soft water can be provided by having |
| A. | storage facilities |
| B. | required amount of ppm |
| C. | high pressure boilers |
| D. | 1ppm |
| Answer» A. storage facilities | |
| Explanation: the continuous supply of soft water can be provided by having storage facilities and also two columns of each resin. | |
| 39. |
The cost of the resins used in the ion exchange process is |
| A. | high |
| B. | low |
| C. | moderate |
| D. | depends on water |
| Answer» A. high | |
| Explanation: the cost of the resins used in the ion exchange process is high and the regeneration of the resins in also a costly process. | |
| 40. |
The mineral free water is not used in |
| A. | pharmaceuticals |
| B. | cosmetics |
| C. | explosives |
| D. | drinking |
| Answer» D. drinking | |
| Explanation: in drinking water some minerals must be present. in pharmaceuticals, cosmetics, explosives and in other manufacturing processes, the mineral free water is used. | |
| 41. |
In which process of water softening, ion exchange phenomenon takes place? |
| A. | lime soda process |
| B. | zeolite process |
| C. | boiling |
| D. | demineralization process |
| Answer» B. zeolite process | |
| Explanation: in the zeolite process, calcium and magnesium are removed from hard water by ion exchange phenomenon. | |
| 42. |
In which process of water softening, the chemicals are added to remove hardness from water? |
| A. | lime soda process |
| B. | zeolite process |
| C. | boiling |
| D. | demineralization process |
| Answer» A. lime soda process | |
| Explanation: in the lime soda process, lime and soda are added to remove temporary and permanent hardness from water. | |
| 43. |
Zeolites are complex compound of |
| A. | aluminium and lime |
| B. | silica and soda |
| C. | aluminium, silica and soda |
| D. | lime and soda |
| Answer» C. aluminium, silica and soda | |
| Explanation: zeolites are complex compound of aluminium, silica and soda. it has the property of removing calcium and magnesium from water and substituting sodium in their place. | |
| 44. |
The color of the artificial zeolite permutit is |
| A. | grey |
| B. | yellow |
| C. | green |
| D. | white |
| Answer» D. white | |
| Explanation: the artificial zeolite permutit has a large and lustrous grain. they are white in color and has an appearance of coarse sand. | |
| 45. |
Natural zeolite is mainly processed from |
| A. | white sand |
| B. | green sand |
| C. | grey sand |
| D. | red sand |
| Answer» B. green sand | |
| Explanation: the natural zeolite is mainly processed from green sand, which is also called as glauconite. it has lesser exchange value than artificial zeolite. | |
| 46. |
The color of the natural zeolite is |
| A. | green |
| B. | grey |
| C. | black |
| D. | blue |
| Answer» A. green | |
| Explanation: the color of the natural zeolite is green as it is processed from glauconite which is green in color. it has an exchange value of 6500-9000gm of hardness per m3 of zeolite. | |
| 47. |
The chemical formula of Permutit is |
| A. | sioal2o3na2o |
| B. | sio2al2o3na2o |
| C. | sio2al2o3nao |
| D. | sio3al2o3na2o |
| Answer» B. sio2al2o3na2o | |
| Explanation: the chemical formula of permutit is sio2al2o3na2o. the increase in the value of sio2 increases its resistance to aggressive attacks. | |
| 48. |
The zeolite process is unsuitable for water containing iron and manganese. |
| A. | true |
| B. | false |
| Answer» A. true | |
| Explanation: iron and manganese bearing water deposit hydroxides on the surface of zeolite or react with zeolite to substitute iron and manganese for sodium, which is an irreversible reaction. this makes the zeolite process unsuitable. | |
| 49. |
The thickness of the layers of filter sand of zeolite softener is |
| A. | 20cm |
| B. | 30cm |
| C. | 40cm |
| D. | 100cm |
| Answer» D. 100cm | |
| Explanation: the thickness of the layers of filter sand of zeolite softener lies in the range of 75 to 150cm and their functioning is similar to the rapid sand filter. | |
| 50. |
Salt cannot be separated from brackish water by freezing. |
| A. | true |
| B. | false |
| Answer» B. false | |
| Explanation: salt can be separated from brackish water by freezing. | |
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