MCQOPTIONS
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MCQOPTIONS
This section includes 32 Mcqs, each offering curated multiple-choice questions to sharpen your Environmental Science knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
The efficiency of chlorine increase by |
| A. | Presence of metallic compounds |
| B. | When the pH of the water increases |
| C. | When the pH of the water decreases |
| D. | Turbid water |
| Answer» D. Turbid water | |
| 2. |
The ozone generators can convert ____ % of feed oxygen into ozone. |
| A. | 1 |
| B. | 5 |
| C. | 1-4 |
| D. | 10 |
| Answer» D. 10 | |
| 3. |
For changing the concentration of disinfectant, the disinfecting efficiency is expressed by |
| A. | C n *t p = Constant |
| B. | C n/ t p = Constant |
| C. | C q * Np = Constant |
| D. | C q / Np = Constant |
| Answer» B. C n/ t p = Constant | |
| 4. |
Bleaching powder contains ______ of available chlorine. |
| A. | 0.16 |
| B. | 0.333 |
| C. | 0.666 |
| D. | 0.999 |
| Answer» C. 0.666 | |
| 5. |
The depth of water while using ultra violet ray treatment for disinfection should be ____ |
| A. | 35cm |
| B. | 46cm |
| C. | 28cm |
| D. | 10cm |
| Answer» E. | |
| 6. |
The amount of hypochlorous acid formed when pH of water is 8 is |
| A. | 95% of total free chlorine |
| B. | 80% of total free chlorine |
| C. | 30% of total free chlorine |
| D. | 5% of total free chlorine |
| Answer» D. 5% of total free chlorine | |
| 7. |
The presence of metallic compounds in water _______ the efficiency of chlorine. |
| A. | Decreases |
| B. | Increases |
| C. | Slightly decreases |
| D. | Remains constant |
| Answer» B. Increases | |
| 8. |
The contact time for disinfection by combined chlorine is |
| A. | 20 minutes |
| B. | 30 minutes |
| C. | 40 minutes |
| D. | 60minutes |
| Answer» E. | |
| 9. |
_______ is the application of chlorine beyond the stage of the break point. |
| A. | Plain chlorination |
| B. | Pre chlorination |
| C. | Super chlorination |
| D. | Double chlorination |
| Answer» D. Double chlorination | |
| 10. |
When turbidity in water increases, the efficiency of chlorine |
| A. | Decreases |
| B. | Increases |
| C. | Slightly increases |
| D. | Remains constant |
| Answer» B. Increases | |
| 11. |
At what pH, the E-Coli bacteria will die in the water? |
| A. | 6 |
| B. | 7 |
| C. | 9 |
| D. | >9.5 |
| Answer» E. | |
| 12. |
The normal dose of chlorine during post chlorination is |
| A. | 0.5-1ppm |
| B. | 0.1-0.2ppm |
| C. | 0.1-0.5ppm |
| D. | 1-2ppm |
| Answer» C. 0.1-0.5ppm | |
| 13. |
The number of organisms in disinfection process can be expressed by |
| A. | Cn *t p = Constant |
| B. | C n/ tp = Constant |
| C. | C q * Np = Constant |
| D. | C q / Np = Constant |
| Answer» D. C q / Np = Constant | |
| 14. |
Ozone is a _______ allotrope of oxygen. |
| A. | Monoatomic |
| B. | Diatomic |
| C. | Triatomic |
| D. | Polyatomic |
| Answer» D. Polyatomic | |
| 15. |
The expression loge N1/N = – kt m Where, m is a constant such that m>1 represents |
| A. | Rate of the kill will remains constant with time |
| B. | Rate of the kill will increase with time |
| C. | Rate of the kill will decrease with time |
| D. | Rate of the kill is directly proportional to time |
| Answer» C. Rate of the kill will decrease with time | |
| 16. |
When the coefficient of dilution is 1, then which of the following statement is correct? |
| A. | Time of contact is more important than dosage |
| B. | The dosage is more important than time of contact |
| C. | Concentration and time are equally important |
| D. | Efficiency of dilution decreases. |
| Answer» D. Efficiency of dilution decreases. | |
| 17. |
The permissible limit of free residual chlorine is |
| A. | 0.02ppm |
| B. | 0.2ppm |
| C. | 1ppm |
| D. | 2ppm |
| Answer» C. 1ppm | |
| 18. |
Which method of disinfection is mainly used in rural areas? |
| A. | Boiling method |
| B. | Excess lime treatment |
| C. | Potassium permanganate treatment |
| D. | Silver treatment |
| Answer» D. Silver treatment | |
| 19. |
Which of the following is most effective in the killing of bacteria present in water? |
| A. | Nascent oxygen |
| B. | Chlorine |
| C. | HOBr |
| D. | I2 |
| Answer» B. Chlorine | |
| 20. |
State whether the following statement is true or false.Iodine is a better disinfectant to kill virus than hypoiodous acid. |
| A. | True |
| B. | False |
| Answer» C. | |
| 21. |
What happens during the breakdown of ozone? |
| A. | CO2 is formed |
| B. | Nascent oxygen is formed |
| C. | CO2 and Nascent oxygen is formed |
| D. | Formation of oxygen and water takes place. |
| Answer» C. CO2 and Nascent oxygen is formed | |
| 22. |
The process of chlorination with hypochlorites is called |
| A. | Super chlorination |
| B. | Pre chlorination |
| C. | Post chlorination |
| D. | Hypo-chlorination |
| Answer» E. | |
| 23. |
What is the chemical formula of bleaching powder? |
| A. | Ca (OCl)2 |
| B. | Ca (OCl) |
| C. | Ca (OCl)3 |
| D. | CaCl2 |
| Answer» B. Ca (OCl) | |
| 24. |
Which color is formed when orthotolidine is oxidized by chlorine? |
| A. | Yellow |
| B. | Orange |
| C. | Green |
| D. | Blue |
| Answer» B. Orange | |
| 25. |
a HIO + b OH- HIO3 + b H2O + b I–. What are the values of a and b respectively in the above equation? |
| A. | 1, 2 |
| B. | 1, 3 |
| C. | 3, 2 |
| D. | 3, 1 |
| Answer» D. 3, 1 | |
| 26. |
The contact time for disinfection by free chlorine is |
| A. | 20 minutes |
| B. | 30 minutes |
| C. | 40 minutes |
| D. | 60minutes |
| Answer» B. 30 minutes | |
| 27. |
Which of the following is termed as free available chlorine? |
| A. | Hypochlorous acid |
| B. | Hypochlorite ions |
| C. | Molecular chlorine |
| D. | Hypochlorous acid, Hypochlorite ions, Molecular chlorine |
| Answer» E. | |
| 28. |
State whether the following statement is true or false.The temperature of disinfection is inversely proportional to the killing of organisms. |
| A. | True |
| B. | False |
| Answer» C. | |
| 29. |
The process of removal of excess chlorine from water is |
| A. | Plain chlorination |
| B. | Dechlorination |
| C. | Super chlorination |
| D. | Double chlorination |
| Answer» C. Super chlorination | |
| 30. |
Which type of chlorine is represented by the red line as shown in figure? |
| A. | Free residual chlorine |
| B. | Ammonia chlorine |
| C. | Combined residual chlorine |
| D. | Residual chloramine |
| Answer» C. Combined residual chlorine | |
| 31. |
Efficiency of dilution decreases rapidly when the coefficient of dilution is |
| A. | 0 |
| B. | 1 |
| C. | <1 |
| D. | >1 |
| Answer» E. | |
| 32. |
Consider the following variables.1. Concentration of disinfectant2. Concentration of organisms3. Temperature4. Time of contactDisinfection is the function of which of the following variables? |
| A. | 1, 2 |
| B. | 1, 2, 3 |
| C. | 1, 2, 3, 4 |
| D. | 2, 3, 4 |
| Answer» D. 2, 3, 4 | |