CWEA LAB ANALYST COMPLETE
SET|UPDATE|GRADED A+
Question : An amperometric titration is often used when
measuring
Correct answer: Residual chlorine
Question : The most important reason for chlorinating
effluent is
Correct answer: Disinfection
Question : Chlorination serves primarily to
Correct answer: Destroy or deactivate disease-producing
microorganisms
Question : When wastewater samples are chlorinated and the
pH is lowered
Correct answer: HCLO is formed Hypochlorous acid
Question : Which of the following constituents is the best
disinfecting agent?
Correct answer: HClO
Question : What is most likely to interfere with the DPD test?
Correct answer: Oxidized manganese
Question : How is N, N-diethyl-p-phenylenediamine more
commonly represented?
Correct answer: DPD
Question : The chlorine residual may be determined using the
reagent
Correct answer: DPD
Question : The quantity of chlorine that is converted to inert
or less active forms of chlorine by substances in wastewater
Correct answer: Total combined chlorine
Question : Before you perform an amperometric titration for
total residual chlornie, what two solutions should be added to the sample?
Correct answer: Kl and acetate buffer (Potassium iodide)
Question : When performing an amperometric titration for
chlorine, how many milliliters of sample should be analyzed?
Correct answer: 200 mL
Question : When using a spectrophotometer to measure
chlorine, what wave length of light should be used?
Correct answer: 515 nm
Question : An effluent with a high level of ammonia nitrogen
has chlorine residual that is mostly
Correct answer: Combined chlorine
Question : The mercuric nitrate titration technique for
measuring chloride is falling into disuse in the laboratory
because the:
Correct answer: technique is lengthy and requires highly
skilled instrument technicians to accurately analyze the samples.
Question : Standard phenylarsine oxide solution (PAO):
Correct answer: should be handled with caution because it is a
severe poison.
Question : Sample Protocol for chloride includes
Correct answer: glass or plastic container with no preservative
Question : Flow proportional sample. If total sample volume
is 1 liter
Correct answer: 100ml
Question : The incubator for the BOD determination should
be monitored and recorded daily. The incubator temperature
should be:
Correct answer: 20 degrees +/-1 degree C
Question : Laboratory data mistakes may be corrected by: