481.
Hardness of water is expressed in equivalents of
A
B
C
D
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Hardness of water is expressed in equivalents of
Hardness of water does not
Make it unfit for drinking
cause difficulty in washing clothes with soaps.
Have any bad effect in boiler
make cooking of food difficult
Hardness in water is caused due to the presence of
Dissolved salts of and
Undissolved
Undissolved salts of and
Dissolved sulfates of Potassium
Hard water is unfit for use in boilers for generating steam because
Water decomposes into and
It produces scales inside the boiler
Its boiling point is high
Hard water does not produce lather inside boiler
Hard water can be softened by passing it through
Ion – exchange resin
sodium silicate
Lime stone
sodium hexa meta phosphate
Estimation of hardness of water by EDTA method is used to determine
Permanent hardness only
all the above
Alkaline hardness
temporary hardness only
Disinfection by ozone is due to liberation of
Molecular Oxygen
oxide
Oxygen
nascent Oxygen
Caustic embrittlement is a type of
scale formation
sludge formation.
Boiler corrosion
conditioning
Caustic embrittlement can be avoided by using
ammonium hydroxide
sodium sulphate
Sodium phosphate
hydrogen
Calgon is used for the removal of
Hardness of water
none of these
Sodium carbonate
permanent hardness of water
Calgon is the trade name given to
Sodium meta phosphate
Calcium phosphate
Sodium silicate
Sodium hexa meta phosphate
Brackish water mainly contains
Turbidity
sodium chloride
Calcium salts
Magnesium salts
Boiler corrosion caused by using high alkaline water in a boiler is called
caustic embrittlement
erosion
Corrosion
boiler corrosion
Blow – down operation cause the removal of
acidity
sodium chloride
Scales
sludges
Biological oxidation processes usually referred as biological treatment, are the most common form of
Tertiary treatment
all of the above
Primary treatment
secondary treatment
A water sample found to possess 16.2 mg/L of . Its hardness in terms of equivalents is
16.2
1000
100
10
Which one of the following three terms is used in the sustainability triangle?
Micro-economics
Planet
Social responsibility
Which of the following is the greenest solvent?
Formaldehyde
Benzene
Ethanol
Water
Which of the following is a challenge for green chemists?
Awareness of the benefits of green chemistry
Developing chemicals that are recyclable
Training for cleaning up chemical spills
Knowing when to reduce and eliminate hazardous waste
Which of the following are among the 12 Principles of Green Chemistry?
Design commercially viable products
Use only new solvents
Use catalysts, not stoichiometric reagents
Re-use waste