500 Best Environmental Engineering- MCQ
Q125). The most commonly used disinfectant for drinking water throughout the world is
a).Alum
b).Nitrogen
c).Lime
d).Chlorine
Correct Answer:
Chlorine
Explanation:
Q126). The ideal method of disinfection of swimming pool water is by
a).Chlorination
b).Lime treatment
c).Ozonisation
d).Ultra violet rays
Correct Answer:
Ozonisation
Explanation:
Q127). The amount of residual chlorine in treated water is determined by the
a).Orthotolodine test
b).Iodometric test
c).Amperometric test
d).All of the above
Correct Answer:
All of the above
Explanation:
Q128). The time of contact for chlorination should be at least
a).5 minutes
b).20 minutes
c).1 hour
d).2 hours
Correct Answer:
20 minutes
Explanation:
Q129). The treatment of water with only chlorine is known as
a).Plain chlorination
b).Post chlorination
c).Pre chlorination
d).De chlorination
Correct Answer:
Plain chlorination
Explanation:
Q130). Pre chlorination
a).Improves coagulation
b).Reduces odours
c).Reduces tastes
d).All of these
Correct Answer:
All of these
Explanation:
Q131). To prevent the formation of crystalline hydrates of ‘ice’ of chlorine, the chlorine supply cylinders are kept at a temperature from
a).10°C to 20°C
b).20°C to 27°C
c).27°C to 37°C
d).38°C to 42°C
Correct Answer:
38°C to 42°C
Explanation:
Q132). Crystalline hydrates of ‘Ice’ of chlorine are formed at a temperature of
a).Below 10°C
b).15°C
c).20°C
d).Above 20°C
Correct Answer:
Below 10°C
Explanation: