CWEA Grade 1 Lab Analyst Practice Test Part 2
Questions and Correct Answers 2026/2027
1. What is chloride?: Major anion found in many natural waters - Can impart salty taste in H2O
2. What increases the concentration of chloride in wastewater?: Chloride in human diet and
softeners flushed into sanitary sewer system
3. 2 most prevalent methods of measuring chloride?: argentometric and mercuric nitrate
4. What is the Argentometric method?: Titration of the sample with a standard solution of silver nitrate
(AgNO3) - Indicator: Chromate ions (CrO4) - End point: reddish silver chromate
5. What is the Mercuric Nitrate method?: Titration with standard mercuric nitrate solution -pH must be
adjusted between 2.3 and 2.8 - Indicator: Diphenyl carbazone - End point: Change from blue to purple in the presence of
mercury
6. Which of the following can be an Interference of the Mercuric Nitrate Method?:
Sulfide, bromide, orthophosphate (over 30 ppm), and iodide
7. Why does the color change in water?
a. Presence of decaying vegetable matter
b. metal ions (ie. iron)
c. industrial and domestic pollution
d. All of the above: d
8. How is color measured: Measured using visual comparison method
9. What is the visual comparison method: Sample compared to standards using matching nessler tubes -
Standards prepared with solution containing chloroplatinate and cobaltous chlorid
10. What is the standard unit for color?: One unit= color resulting from 1 mg of platinum/L
11. What is 2-color reporting?: True and Apparent
12. Define True color: Color from suspended solids, determine using sample treated to remove turbidity
13. What is Apparent Color?: Color from both dissolved and suspended solids
14. What is Conductivity?: H2O capability to pass electrical flow
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Questions and Correct Answers 2026/2027
1. What is chloride?: Major anion found in many natural waters - Can impart salty taste in H2O
2. What increases the concentration of chloride in wastewater?: Chloride in human diet and
softeners flushed into sanitary sewer system
3. 2 most prevalent methods of measuring chloride?: argentometric and mercuric nitrate
4. What is the Argentometric method?: Titration of the sample with a standard solution of silver nitrate
(AgNO3) - Indicator: Chromate ions (CrO4) - End point: reddish silver chromate
5. What is the Mercuric Nitrate method?: Titration with standard mercuric nitrate solution -pH must be
adjusted between 2.3 and 2.8 - Indicator: Diphenyl carbazone - End point: Change from blue to purple in the presence of
mercury
6. Which of the following can be an Interference of the Mercuric Nitrate Method?:
Sulfide, bromide, orthophosphate (over 30 ppm), and iodide
7. Why does the color change in water?
a. Presence of decaying vegetable matter
b. metal ions (ie. iron)
c. industrial and domestic pollution
d. All of the above: d
8. How is color measured: Measured using visual comparison method
9. What is the visual comparison method: Sample compared to standards using matching nessler tubes -
Standards prepared with solution containing chloroplatinate and cobaltous chlorid
10. What is the standard unit for color?: One unit= color resulting from 1 mg of platinum/L
11. What is 2-color reporting?: True and Apparent
12. Define True color: Color from suspended solids, determine using sample treated to remove turbidity
13. What is Apparent Color?: Color from both dissolved and suspended solids
14. What is Conductivity?: H2O capability to pass electrical flow
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