LESSON 2
PRACTICE EXERCISE
ANSWER KEY AND FEEDBACK
Item
Correct Answer and Feedback
1.
D. Anytime over seven days is considered long-term consumption. (Page 2-4, para 3)
2.
C. Seven days is the maximum short-term consumption. (Page 2-4, para 3)
3.
C. Chlorine is added to water after the RO process to avoid its harming the membranes of the
ROWPU. (Page 2-4, para 6)
4.
A. As the pH changes from 5 to 9, the form of the chlorine residual changes from hypochlorous
acid (HOC1) to hypochlorite ion (OCI-). (Page 2-4, para 5)
5.
B. After 30 minutes contact time at a pH between 6.5 and 7.5, the standard for chlorine residual
is 2.0 ppm. (Page 2-4, para 6)
QM4916
2-14
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