MCQOPTIONS
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MCQOPTIONS
This section includes 36 Mcqs, each offering curated multiple-choice questions to sharpen your Environmental Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Which of the following is the second step for calculating the amount of lime and soda? |
| A. | Identification of lime and soda for different salts |
| B. | Calculation of CaCO3 equivalents |
| C. | Calculation of lime requirements |
| D. | Calculation of soda requirements |
| Answer» C. Calculation of lime requirements | |
| 2. |
In lime-soda process, no exchange of ions occurs. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 3. |
In lime soda process, capital cost is ___________ whereas operational expenses are __________ |
| A. | High, low |
| B. | High, high |
| C. | Low, low |
| D. | Low, high |
| Answer» E. | |
| 4. |
The residual hardness in lime-soda process is ___________ |
| A. | 0-2 ppm |
| B. | 5-15 ppm |
| C. | 15-50 ppm |
| D. | 50-70 ppm |
| Answer» D. 50-70 ppm | |
| 5. |
For the softening of one mole of magnesium bicarbonate, the number of mole of lime required is? |
| A. | 2 |
| B. | 3 |
| C. | 4 |
| D. | 5 |
| Answer» B. 3 | |
| 6. |
What is the molecular formula of lime? |
| A. | CaCO3 |
| B. | Al(OH)3 |
| C. | Ca(OH)2 |
| D. | Mg(OH)2 |
| Answer» D. Mg(OH)2 | |
| 7. |
The sludge in water softening accelerator is deposited at ____________ |
| A. | Sedimentation tank |
| B. | Reaction zone |
| C. | Concentrator |
| D. | Secondary mixing zone |
| Answer» D. Secondary mixing zone | |
| 8. |
What is the detention time of a water softening accelerator? |
| A. | 1-6minutes |
| B. | 20minutes |
| C. | 30 minutes |
| D. | 1-2hours |
| Answer» E. | |
| 9. |
Which filter is normally used in the lime soda treatment plant? |
| A. | Slow sand filter |
| B. | Rapid sand filter |
| C. | Dual media filter |
| D. | Mixed media filter |
| Answer» C. Dual media filter | |
| 10. |
The minimum reaction time allowed in the recarbonation basin is ____________ |
| A. | 5minutes |
| B. | 10minutes |
| C. | 15minutes |
| D. | 20minutes |
| Answer» E. | |
| 11. |
The detention period of a lime soda treatment plant is ____________ |
| A. | 1hour |
| B. | 3hours |
| C. | 2-4hours |
| D. | 4-7hours |
| Answer» D. 4-7hours | |
| 12. |
Softening chemicals, lime and soda do not depend on ____________ |
| A. | Free carbon dioxide present |
| B. | Non carbonate hardness |
| C. | Total magnesium |
| D. | Carbonate hardness |
| Answer» E. | |
| 13. |
Which chemical is used for removing the permanent hardness of Calcium chloride? |
| A. | Lime |
| B. | Chlorine |
| C. | Soda |
| D. | Both lime and soda |
| Answer» C. Soda | |
| 14. |
The temperature at which the softening of water takes place by lime soda process is ____________ |
| A. | 10o-21oC |
| B. | 20o-30oC |
| C. | 39o-45oC |
| D. | 90oC |
| Answer» B. 20o-30oC | |
| 15. |
The time required for the mixing of lime and soda in lime soda process is _____________ |
| A. | 10min |
| B. | 20min |
| C. | 40min |
| D. | 80 min |
| Answer» D. 80 min | |
| 16. |
The permanent hardness can be removed by adding lime and soda. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 17. |
IN_LIME-SODA_PROCESS,_NO_EXCHANGE_OF_IONS_OCCURS.?$ |
| A. | True |
| B. | False |
| Answer» B. False | |
| 18. |
WHICH_FILTER_IS_NORMALLY_USED_IN_THE_LIME_SODA_TREATMENT_PLANT??$ |
| A. | Slow sand filter |
| B. | Rapid sand filter |
| C. | Dual media filter |
| D. | Mixed media filter |
| Answer» C. Dual media filter | |
| 19. |
The sludge in water softening accelerator is deposited at$ |
| A. | Sedimentation tank |
| B. | Reaction zone |
| C. | Concentrator |
| D. | Secondary mixing zone |
| Answer» D. Secondary mixing zone | |
| 20. |
Which_of_the_following_is_the_second_step_for_calculating_the_amount_of_lime_and_soda?$ |
| A. | Identification of lime and soda for different salts |
| B. | Calculation of CaCO<sub>3</sub> equivalents |
| C. | Calculation of lime requirements |
| D. | Calculation of soda requirements |
| Answer» C. Calculation of lime requirements | |
| 21. |
What_is_the_detention_time_of_a_water_softening_accelerator?$ |
| A. | 1-6minutes |
| B. | 20minutes |
| C. | 30 minutes |
| D. | 1-2hours |
| Answer» E. | |
| 22. |
In lime soda process, capital cost is ___________ whereas operational expenses are _________? |
| A. | High, low |
| B. | High, high |
| C. | Low, low |
| D. | Low, high |
| Answer» E. | |
| 23. |
What is the pH at which recarbonation should be done? |
| A. | 7 |
| B. | 4.5 |
| C. | 8.2 |
| D. | 9.5 |
| Answer» E. | |
| 24. |
The residual hardness in lime-soda process is |
| A. | 0-2 ppm |
| B. | 5-15 ppm |
| C. | 15-50 ppm |
| D. | 50-70 ppm |
| Answer» D. 50-70 ppm | |
| 25. |
The minimum reaction time allowed in the recarbonation basin is |
| A. | 5minutes |
| B. | 10minutes |
| C. | 15minutes |
| D. | 20minutes |
| Answer» E. | |
| 26. |
For the softening of one mole of magnesium bicarbonate, the number of mole of lime required is |
| A. | 2 |
| B. | 3 |
| C. | 4 |
| D. | 5 |
| Answer» B. 3 | |
| 27. |
The detention period of a lime soda treatment plant is |
| A. | 1hour |
| B. | 3hours |
| C. | 2-4hours |
| D. | 4-7hours |
| Answer» D. 4-7hours | |
| 28. |
What is the function of coagulant? |
| A. | It helps in the formation of fine precipitate |
| B. | It helps in the formation of coarse precipitate |
| C. | It helps in increasing the solubility |
| D. | It helps in increasing the boiling point |
| Answer» C. It helps in increasing the solubility | |
| 29. |
Softening chemicals, lime and soda do not depend on |
| A. | Free carbon dioxide present |
| B. | Non carbonate hardness |
| C. | Total magnesium |
| D. | Carbonate hardness |
| Answer» E. | |
| 30. |
Which of the following is not used as a coagulant in lime-soda process? |
| A. | Alum |
| B. | Calcium bicarbonate |
| C. | Aluminium sulphate |
| D. | Sodium aluminate |
| Answer» C. Aluminium sulphate | |
| 31. |
Which chemical is used for the removing the permanent hardness of Calcium chloride? |
| A. | Lime |
| B. | Chlorine |
| C. | Soda |
| D. | Both lime and soda |
| Answer» C. Soda | |
| 32. |
Which of the following is not a precipitate in lime-soda process? |
| A. | CaCO<sub>3</sub> |
| B. | Fe(OH) <sub>3</sub> |
| C. | Al(OH) <sub>3</sub> |
| D. | Al<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub> |
| Answer» E. | |
| 33. |
The temperature at which the softening of water takes place by lime soda process is |
| A. | 10<sup>o</sup>-21<sup>o</sup>C |
| B. | 20<sup>o</sup>-30<sup>o</sup>C |
| C. | 39<sup>o</sup>-45<sup>o</sup>C |
| D. | 90<sup>o</sup>C |
| Answer» B. 20<sup>o</sup>-30<sup>o</sup>C | |
| 34. |
What is the molecular formula of soda? |
| A. | Na<sub>2</sub>CO<sub>3</sub> |
| B. | Al<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub> |
| C. | Mg(OH) <sub>2</sub> |
| D. | Ca(OH) <sub>2</sub> |
| Answer» B. Al<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub> | |
| 35. |
The time required for the mixing of lime and soda in lime soda process is |
| A. | 10min |
| B. | 20min |
| C. | 40min |
| D. | 80 min |
| Answer» D. 80 min | |
| 36. |
State whether the following statement is true or false. |
| A. | |
| B. | True |
| Answer» B. True | |