1.
Chlorine disinfects water much slower at a pH around 7.0 than at a pH over 8.0.
2.
Excessive turbidity will greatly increase the efficiency of the disinfecting chemical or process.
3.
Organics found in the water can consume great amounts of disinfectants while forming unwanted compounds.
4.
The demand for chlorine by reducing agents must be satisfied before chlorine becomes available to accomplish disinfection.
5.
Chlorine by itself is nonflammable and nonexplosive, but it will support combustion.
6.
The chlorine ion has no disinfecting power and produces no chlorine residual.
7.
The use of hypochlorite to treat potable water achieves the same result as chlorine gas.
8.
Public water supplies are normally chlorinated up to the breakpoint.
9.
Ammonia must be present to produce the breakpoint chlorination curve from the addition of chlorine.
10.
For extremely clean source waters, there may be virtually no Giardia or viruses and achieving 3-log or 4-log inactivation levels will be impossible and not necessary.
11.
Plastic containers are commonly used for storage of chlorine gas.
12.
When chlorine gas condenses to liquid (reliquifies), the liquid chlorine may plug the chlorine supply lines.
13.
When operating a hypochlorinator; you should compare the actual chlorine dose applied to the water being treated with the desired chlorine dose in milligrams per liter.
14.
When looking for a chlorine leak, never apply ammonia solutions directly to any valve because an acid will form that will eat away the valve fittings.
15.
Very often when consumers complain about chlorine tastes in their drinking water, the chlorine dose has been inadequate.
16.
Sodium chlorite is very combustible around organic compounds.
17.
Chlorine is a gas that is 2.5 times lighter than air.
18.
Hypochlorite is much more hazardous than gaseous chlorine.
19.
All lamps within an ultraviolet (UV) system are identical (type, length, diameter, power, and output).
20.
Maintenance on ultraviolet (UV) systems requires cleaning the quartz sleeves and changing the lamps.
21.
Ozone is normally generated on site because it is very unstable and decomposes to elemental oxygen in a short time after generation.
22.
Why are there very few natural waters that are safe to drink without treatment of some kind?
A. 
Because of advances in the field of pollution detection technology.
B. 
Because of population growth and related pollution of waters.
C. 
Because of the excessive demands on operators' time, which have prevented adequate O & M.
D. 
Because of the lack of maintenance and deterioration of treatment equipment.
23.
What is the chlorine demand?
A. 
The amount of chlorine needed to satisfy the chlorine demand and the amount of chlorine residual needed for disinfection.
B. 
The amount of chlorine sufficient to kill the microorganisms present in the water supply
C. 
The amount of chlorine that reacts with the organic and inorganic materials in water.
D. 
The total amount of all compounds with disinfecting properties plus any remaining free (uncombined) chlorine.
24.
How can the formation of suspected carcinogenic compounds (trihalomethanes) be prevented as a result of the chemical reactions that take place between organic materials and chlorine?
A. 
By limiting the amount of prechlorination and by removing the organic materials prior to chlorination.
B. 
By neutralizing the formation of carcinogenic compounds.
C. 
By removing any doubt or suspicion about the chemical reactions.
D. 
By revealing the direction of the chemical reactions.
25.
What is breakpoint chlorination?
A. 
Addition of chlorine to water until the chlorine demand has been satisfied.
B. 
Compounds formed by the reaction of hypochlorous acid (or aqueous chlorine) with ammonia.
C. 
Organic compounds combined with chlorine.
D. 
Phenolic compounds (carbolic acids) combined with chlorine.