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WorksheetsBoiler troubles
Total questions: 38
Worksheet time: 19mins
Scale formation in boilers causes
no loss of heat
wastage of heat
increase in efficiency
none of the above
Scale formation in boilers causes
no loss of heat
wastage of heat
increase in efficiency
none of the above
Blow-down operation causes the removal of
SCALES
SLUDGES
BOTH OF THESE
HOT WATER ONLY
Hard water is unfit for use in boilers for “steam raising” because
its boiling point is higher
steam generated at a high pressure
it leads to scale formation inside the boiler
water undergoes decomposition in to oxygen and hydrogen.
Is hard water need to be converted to soft water before fed in to boilers?
Always
Not always
rare
optional
Coagulants help in the settling of
suspended impurities only
fine suspended matter only
colloidal particles only
both (B) and (C)
Total hardness equals
Temporary hardness
Permanent hardness
Temporary hardness + Permanent Hardness
Temporary hardness - Permanent Hardness
Temporary hardness is due to the presence of
Bicarbonates of Ni & Mg
Bicarbonates of Ca & Mg
Chlorides of Ca & Ni
Sulphates of Mg & Ca
Boiler feed water contains hardness of
0 PPM
< 0.2 PPM
> 0.2 PPM
= 0.2 PPM
If your boiler water contains oil and turbidity causing ions the resulting boiler troubles are
Scales & Sludges
Priming & Foaming
Caustic Embrittlement
Boiler Corrosion
The indicator employed for detection of hardness during titration with EDTA solution is
Methyl orange
Phenolphthalein
Eriochrome-Black-T
Diphenyl amine
Complete the following sentence "Hard water is water that
forms a lather easily with water.
does not form a lather easily with water
_________ hardness can be removed by boiling while __________ hardness cannot by removed by boiling.
(a)
Which of the following would be considered to be caused by temporary hardness in water?
Blocking of pipes with limescale
Furring of kettles
Scum formation when using soap
Coating of heating element of dishwasher, shower, washing machine with limescale
Which of the following are methods used to remove permanent hardness in water?
Distillation
Adding washing soda crystals
Boiling the water
Using an ion exchange resin
The removal of temporary hardness in water that is heated, is represented by which of the following equations?
H2O + CO2 ➡️ H2CO3
H2CO3 + CaCO3 ➡️ Ca(HCO3)2
Ca(HCO3)2 ➡️ CaCO3 + CO2 + H2O
When carbon dioxide reacts with water in the air, a weak acid called carbonic acid is produced. What is the formula of carbonic acid?
(a)
Carbonic acid falls as rainwater that is slightly acidic. This reacts with calcium carbonate, which is limestone rock, producing a soluble chemical that causes temporary hardness in water. What is the correct formula for this soluble compound?
(a)
When cold water containing temporary hardness is heated, an insoluble substance precipitates out of the water. What is the formula for this insoluble precipitate?
CaCO3
CaCO3
CO2
H2O
_________ is the amount of oxygen dissolved in water.
dissolved carbon dioxide
dissolved oxygen
turbidity
pH
What does a pH of 7 mean?
acid
base
neutral
Which beaker in the image has the highest turbidity?
A
B
C
D
Which conditions would be best for growing plants?
high dissolved oxygen, high nitrates, high phosphates
low dissolved oxygen, low nitrates, low phosphates
high dissolved oxygen, low nitrates, low phosphates
low dissolved oxygen, high nitrates, high phosphates
Hardness in water is caused by the presence of:
Sodium chloride
Sodium carbonate
Calcium chloride
Potassium nitrate
Permanent hardness in water is caused by the presence of:
Calcium bicarbonate
Magnesium sulfate
Both of them
None of them
Water is hard when it contains:
Acid solution
Precipitate in suspension
Dissolved sodium salts
Dissolved Ca and Mg salts
Which of the following does not cause the permanent hardness in water?
Nitrates
Sulphates
Chlorides
Bicarbonates
In _____________ when the water is heated then the soluble salts turns into insoluble ones and removed by filtration.
Temporary hardness
Permanent hardness
Non-carbonate
Non-alkaline
Scale formation in boilers causes
no loss of heat
wastage of heat
increase in efficiency
none of the above
What is the function of a boiler?
to heat water to make steam
to heat water to make spaghetti
to transform liquid into a mist
to mix air and fuel
True or false. When water is heated to its boiling point, it changes from a liquid to a vapor.
true
false
hardness is a measure of scale forming __ dissolved in water
minerals
pollutants
gases
none of the above
scale buildup on the water side of a steam boiler is caused by ___
an impure water supply
scale in raw water
improper boiler water treatment
none of the above
boiler water is treated to prevent...
scale
oxygen pitting
caustic embrittlement
all of the above
