A. Boiling
B. Adding Ca(OH)2
C. Boiling it with Na2CO3
D. None of these
Related Mcqs:
- Permanent hardness of water can be removed by____________________?
A. Simply boiling
B. Adding alum
C. Passing it through cation & anion exchangers
D. All (A), B. and (C) - Permanent hardness of water can be removed by_________________?
A. Addition of soda ash to it
B. Treating it with zeolites
C. Passing it through sodium hexametaphosphate
D. All A , B, and C. - Zeolite removes both temporary as well as permanent hardness of water by precipitating calcium and magnesium present in water as insoluble zeolites. Used zeolite is regenerated by flushing with the solution of_____________________?
A. Calcium sulphate
B. Sodium chloride
C. Sodium sulphate
D. Magnesium chloride - Temporary hardness of water can be removed by__________________?
A. Addition of alum (a coagulant)
B. Boiling
C. Filtration (through gravity sand filter)
D. Addition of lime - Which of the following processes can remove both temporary as well as permanent hardness of water ?
A. Filtration
B. Boiling
C. Distillation
D. None of these - Which of the following is not responsible for causing permanent hardness of water ?
A. Ca(HCO3)2
B. CaCl2
C. MgCl2
D. None of these - Permanent hardness of water is due to the presence of calcium & magnesium __________________?
A. Bi-carbonates
B. Sulphates & chlorides
C. Carbonate
D. None of these - Magnesium and calcium ______________ cause temporary hardness of water ?
A. Carbonates
B. Bicarbonates
C. Phosphates
D. Sulphates - Very fine suspended and colloidal impurities are removed from water by a process called___________________?
A. Sedimentation
B. Coagulation
C. Disinfection
D. Softening - Liquefaction of gases cannot be done by___________________?
A. Exchange of heat with colder stream
B. Adiabatic expansion through a throttle valve (Joule-Thomson expansion)
C. Merely compressing it beyond critical pressure
D. Adiabatic expansion against a piston or in a turbine
