D2 FINAL PAPER PRACTICE SOLUTION
TESTED QUESTIONS WITH FULL ANSWERS
●● True or False: A cross-connection is usually defined as a connection
between a potable water system and a non-potable water system.
Answer: True
●● True or False: An air gap separation provides the highest degree of
protection from backflow and back-siphonage.
Answer: True
●● True or False: Disinfection is the same as sterilization
Answer: False, Disinfection inactivates the bacteria not allowing it to
reproduce where sterilization complete kills the bacteria.
●● True or False: A residual of free chlorine of 0.2 mg/l should be
present at all points within a water system
Answer: True
●● True or False: Compared to gas chlorine or laundry bleach, 65%
HTH chlorine is better suited for water distribution due to its special
formulation.
,Answer: False
●● True or False: Hypochlorite is much more hazardous than gaseous
chlorine.
Answer: False
●● True or False: The presence of a free chlorine should be present at all
points within a distribution system, at all times.
Answer: True
●● True or False: Sodium hypochlorite (a chlorine compound) is usually
supplied in dry form, as a powder or as a pellet.
Answer: False, as a dilute aqueous solution
●● True or False: When chlorine reacts with moisture, it forms two acids
hydrochloric and acetic acids.
Answer: False
●● True or False: The process of disinfection is designed to inactivate
bacterial organisms. The process of inactivation inhibits the ability of the
organism to divide or reproduce and therefore, causes the organism to
die.
Answer: True
,●● True or False: Oxygen levels under 19.5 percent are adequate for
worker's respiratory needs when performing work in a confined space.
Answer: False, it must be at least 19.5%.
●● True or False: In water distribution operations, dosage is defined as
the weight of a given chemical applied to a specific volume of water.
Answer: True
●● True or False: Coliforms are used to measure the bacteriological
quality of drinking (potable) water because the test indicates fecal
contamination where specific disease-producing organisms are not easily
isolated and identified.
Answer: True
●● True or False: All Coliforms are pathogenic
Answer: False, coliforms is a living organism that is used to detect other
pathogens living in the water.
●● True or False: A Blue color after 24 hours is an indication of fecal
coliform in the Colilert Test.
Answer: False, Yellow/fluorescent wells
●● True or False: A white cloud will form in the presence of ammonia if
leaking chlorine is detected
, Answer: True
●● True or False: The basic safety rule to follow prior to opening any
chemical container or using any chemical in water distribution is to read
the label
Answer: True
●● True or False: The leading cause of fatalities in confined spaces is
being struck by falling objects.
Answer: False, asphyxiation, oxygen deficiency, or from exposure to
toxic atmospheres.
●● True or False: The term "Lock-Out" means to block the flow of
energy to equipment and keep it blocked by placing a lock to prevent
accidental start-up
Answer: True
●● True or False: The term "Tag-Out" means to place a tag on the power
source to identify yourself and the purpose of the Lock-Out, and to warn
other not to turn the power back on.
Answer: True
●● True or False: Sacrificial anodes are easily corroded materials
deliberately installed in a pipe to be sacrifices to corrosion leaving the
rest of the system relatively corrosion free.