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WorksheetsBOILER TROUBLES 22-23
Total questions: 20
Worksheet time: 10mins
Which of the following is used for controlling boiler corrosion due to dissolved salts?
a. HCl
b.NaHSO4
c.NaOH
d. Na2CO3
Which of the substance causes caustic embrittlement?
a. Na2CO3
b. dissolved salts
c. Oil and Grease
d. none of the above
Dissolved oxygen in boiler water is removed by
(a)
Which of the following is reason for boiler corrosion?
a. dissolved Co2
b dissolved O2
c. dissolved salts
d. all 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.
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
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)
boiler water is treated to prevent...
scale
oxygen pitting
caustic embrittlement
all of the above
