Certification Action Line features questions and answers typical of those appearing in Water Quality Association (WQA) certification examinations. Some answers may not satisfy everyone or every condition.
1. Chlorine is a member of the ______ family.
a) alkali
b) alkaline earth
c) halogen
d) actinide
2. Chlorine has ___________ uses.
a) diverse
b) limited
3. Chlorine compounds in water form _____.
a) sodium hypochlorite
b) calcium hypochlorite
c) hypochlorous acid
d) hypochlorite ion
4. ________ is a stronger oxidant and has greater biocide efficacy. a) Hypochlorous acid (HOCl) b) Hypochlorite ion (OCl
–)
5. Reactions with ammonia to form chloramines can be overcome by __________.
a) chlorine gas
b) high test chlorine
c) breakpoint chlorination
6. Chlorine demand can be increased by ___________ in water. a) ferrous iron (Fe
++) b) manganese (Mn
++) c) sulfides (S
=) d) humic organic substances e) pollen f) all of the above7. Compared to chlorine, chlorine dioxide (ClO
2) is a ______________ powerful water disinfectant. a) more b) less8. Chlorine dioxide is purchased from a supply house in the form of sodium chlorite (NaClO
2). a) True b) False9. The treatment of natural waters with chlorine dioxide results in these by-product formations. a) chloroform and other trihalomethanes b) chlorite ion (ClO
2-) c) chloramines d) chlorate ion (ClO
3-)
10. High pH _____________ the effectiveness of chlorine dioxide disinfection and oxidation in water.
a) increases
b) decreases
c) does not affect
