CERTIFIED WATER
TECHNOLOGIST CWT
PRACTICE EXAM
Question 1: A water sample changes from pH 7.0 to pH 6.0. The hydrogen ion
concentration becomes approximately:
Choices:
1) One-tenth as great 2) The same 3) Ten times as great 4) One hundred times as great
Correct Answer: Ten times as great
Explanation: A one-unit decrease in pH corresponds to about a tenfold increase in hydrogen ion activity.Page 1
Question 2: Which ions are the primary contributors to conventional water
hardness?
Choices:
1) Sodium and chloride 2) Calcium and magnesium 3) Iron and nitrate 4) Potassium and sulfate
Correct Answer: Calcium and magnesium
Explanation: Water hardness is caused mainly by dissolved calcium and magnesium ions and is commonly reported as CaCO3 equivalents.Question 3: The principal role of alkalinity in water treatment is to:
Choices:
1) Bu�er against acid addition 2) Increase dissolved oxygen 3) Remove suspended solids 4) Convert hardness to sodium
Correct Answer: Bu�er against acid addition
Explanation: Alkalinity is acid-neutralizing capacity and helps resist rapid pH change.Page 2
Question 4: Conductivity is most useful as a rapid indicator of:
Choices:
1) Total dissolved ionic content 2) Bacterial count 3) Suspended solids only 4) Dissolved oxygen only
Correct Answer: Total dissolved ionic content
Explanation: Conductivity re�ects the ability of dissolved ions to carry electrical current and often tracks ionic concentration.Question 5: A 1.0% by weight solution contains how many pounds of active chemical in 500 lb of solution?
Choices:
1) 2.5 lb 2) 5 lb 3) 10 lb 4) 50 lb
Correct Answer: 5 lb
Explanation: 0.01 × 500 lb = 5 lb active chemical.
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