CPO Certified Pool Operator Exam Questions and Answers (Verified Answers) Question 1: Whole range chlorine in a pool: ____ to _____
CORRECT ANSWER : 1, 5
Question 2: Ideal range chlorine in a pool: ____ to _____
CORRECT ANSWER : 2, 4
Question 3: Whole range chlorine in a spa: ____ to _____
CORRECT ANSWER : 2, 10
Question 4: Ideal range chlorine in a spa: ____ to _____
CORRECT ANSWER : 3, 5
Question 5: 4 types of solid chlorine
CORRECT ANSWER : calcium hypochlorite, lithium
hypochlorite, trichlor, dichlor
Question 6: Liquid chlorine
CORRECT ANSWER : sodium hypochlorite (NaOCl)
Question 7: How active is gas chlorine
CORRECT ANSWER : 100%
Question 8: The active killing form of chlorine in water
CORRECT ANSWER : hypochlorous acid (HOCl)
Question 9: HOCl = ______
CORRECT ANSWER : H+ (hydrogen ion) + OCl-
(hypochlorite ion)
Question 10: Most common granular chlorine (pH range)
CORRECT ANSWER : calcium hypochlorite (8.5 - 11, used
to super chlorinate water)
Question 11: Not common form of chlorine due to low active
strength (pH)
CORRECT ANSWER : lithium hypochlorite (10.8)
Question 12: Tablet/stick chlorine usually used in erosion
feeder (pH - what will it do?)
CORRECT ANSWER : trichlor (2.8 - 3.5, lower alkalinity
and pH over time)
Question 13: Salt used as a disinfectant (pH)
CORRECT ANSWER : dichlor (6.7 - common in vinyl lined
pools)
Question 14: Most common type of chlorine used (pH)
CORRECT ANSWER : sodium hypochlorite (NaOCl - 13)
Question 15: ______ needs special training to use and has a
pH of ____ and will _____ when added to water
CORRECT ANSWER : gas chlorine, 0, lower pH
Question 16: Chlorine is most effective as a pH of _____
CORRECT ANSWER : 7.5
Question 17: Active disinfectant in the water
CORRECT ANSWER : free chlorine (FC)
Question 18: FC is determined by the ______ test and is
maintained between ____ and ____ ppm
CORRECT ANSWER : DPD, 2, 4
Question 19: Equal to the amount of hypochlorous acid
(HOCl) and the amt of hypochlorite ions (OCl-)
CORRECT ANSWER : free chlorine (fc)
Question 20: The result of free chlorine reacting with organic
compounds
CORRECT ANSWER : combine chlorine (CC)
Question 21: Common name and max for pools and spas for
combine chlorine