Permanent hard water is softened by addition of
- MgCO3
- CaCO3
- Na2CO3
- BaCO3
Submitted by :- Muhammad Nawaz
Temporary hard water is softened on industrial scale by adding
- Ca(OH)2
- Mg(OH)2
- KOH
- NaOH
Submitted by :- Muhammad Nawaz
Permanent hardness of water is due to
- Sulphate of Ca
- Sulphate of Mg
- Chloride of Ca
- All of these
Submitted by :- Muhammad Nawaz
Water is often treated with chlorine to:
- Increase oxygen content
- Remove suspended particles
- Remove hardness
- Kill germs
Submitted by :- Muhammad Nawaz
Biodegradable pollutant is:
- Plastic
- Sewage
- Asbestos
- Mercury
Submitted by :- Muhammad Nawaz
The minimum value of DO required for water to be pure is:
- 1 ppm
- 2 ppm
- 3 ppm
- 4 ppm
Submitted by :- Muhammad Nawaz
Which of the following is secondary pollutant?
- PAN
- CO₂
- CO
- Aerosol
Submitted by :- Muhammad Nawaz
Which statement is/are true regarding particulate matter?
- They are responsible for cloud and fog formation
- They determine the heat balance of the earth through reflection of radiation
- They are responsible for several catalytic reactions in the atmosphere
- All of these
Submitted by :- Muhammad Nawaz
Earth is protected from UV radiations by which of the following?
- Carbon dioxide layer
- Oxygen layer
- Troposphere
- Ozone layer
Submitted by :- Muhammad Nawaz
Ozone depletion in stratosphere will result in which of the following?
- Increased incidence of skin cancer
- Forest fires
- Global warming
- Acid rain
Submitted by :- Muhammad Nawaz