When faced with a licensing exam, don't struggle with test anxiety! Use the question below and others from our Exam Study Guide series to study and prepare for exam questions. Take a look at this sample water treatment licensing question along with an explanation of the correct answer.

Sample question:

What chemical or chemical compound will lower pH?

A) Chlorine gas
B) Calcium hypochlorite
C) Sodium hypochlorite
D) Sodium hydroxide

Answer: When chlorine gas is mixed with water a chemical reaction takes place and hypochlorous acid is formed, which lowers the pH. So, the correct answer is A.

Reference: Water Treatment Plant Operation. 5th Edition, Volume ll, California State University, Sacramento. Page 80.

About the author
Drew Hoelscher is the program director of drinking water operations at the Environmental Resources Training Center (ERTC) in Edwardsville, Illinois.