TCOT - TEST 2: SOFTENING EXAM
QUESTIONS AND ANSWERS. VERIFIED
2026.
How does quicklime react with water? - ANS Gets hot enough to cause burns
What is one wat to show that alkalinity is not the same thing as pH? - ANS Water does not
have to have a high pH to have a high alkalinity
What is the most common method of disposal for sludge created by the softening process? -
ANS Sanitary sewer disposal
Determine the total hardness as CaCO3 (2.497) for a sample of water with a calcium content of
50 milligrams per liter (mg/L) and a magnesium (4.118) content of 10 mg/L. - ANS 166.2
mg/L as CaCO3
What is the purpose of the resin in an ion exchange softener - ANS Serves as a medium for
ion exchange to take place
What is the water or wastewater's capacity to neutralize acids? - ANS Alkalinity
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
, What is the danger of allowing lime and alum to mix? - ANS Explosions within closed bins
The alkalinity of a water is 125 milligrams per liter (mg/L) as CaCO3 and the total hardness is
140 mg/L as CaCO3. What is the noncarbonate hardness in mg/L as CaCO3? - ANS 15 mg/L as
CaCO3
How can the concentration of chloride ions in milligrams per liter be converted to CaCO3
equivalents? - ANS Multiply by 1.41
How can the equivalent weight of most elements be calculated? - ANS Divide the molecular
weight by the valence
What will result from strong acids being used in recarbonation rather than carbon dioxide? -
ANS Calcium carbonate precipitates will not form
What term best describes a positively charged ion in an electrolyte solution? - ANS Cation
How much soda ash is required in pounds per minute to remove 75 milligrams per liter of
noncarbonate hardness as CaCO3 from a flow of 3.4 million gallons per day? - ANS 1.6 lb/min
What does a negative Langelier Index reading indicate about a water - ANS It is corrosive
Which water treatment chemicals increase alkalinity ? - ANS Calcium hypochlorite and
hydrated lime
What is water hardness a measure of? - ANS The soap- or detergent-consuming power of
water
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
QUESTIONS AND ANSWERS. VERIFIED
2026.
How does quicklime react with water? - ANS Gets hot enough to cause burns
What is one wat to show that alkalinity is not the same thing as pH? - ANS Water does not
have to have a high pH to have a high alkalinity
What is the most common method of disposal for sludge created by the softening process? -
ANS Sanitary sewer disposal
Determine the total hardness as CaCO3 (2.497) for a sample of water with a calcium content of
50 milligrams per liter (mg/L) and a magnesium (4.118) content of 10 mg/L. - ANS 166.2
mg/L as CaCO3
What is the purpose of the resin in an ion exchange softener - ANS Serves as a medium for
ion exchange to take place
What is the water or wastewater's capacity to neutralize acids? - ANS Alkalinity
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
, What is the danger of allowing lime and alum to mix? - ANS Explosions within closed bins
The alkalinity of a water is 125 milligrams per liter (mg/L) as CaCO3 and the total hardness is
140 mg/L as CaCO3. What is the noncarbonate hardness in mg/L as CaCO3? - ANS 15 mg/L as
CaCO3
How can the concentration of chloride ions in milligrams per liter be converted to CaCO3
equivalents? - ANS Multiply by 1.41
How can the equivalent weight of most elements be calculated? - ANS Divide the molecular
weight by the valence
What will result from strong acids being used in recarbonation rather than carbon dioxide? -
ANS Calcium carbonate precipitates will not form
What term best describes a positively charged ion in an electrolyte solution? - ANS Cation
How much soda ash is required in pounds per minute to remove 75 milligrams per liter of
noncarbonate hardness as CaCO3 from a flow of 3.4 million gallons per day? - ANS 1.6 lb/min
What does a negative Langelier Index reading indicate about a water - ANS It is corrosive
Which water treatment chemicals increase alkalinity ? - ANS Calcium hypochlorite and
hydrated lime
What is water hardness a measure of? - ANS The soap- or detergent-consuming power of
water
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
