Scale formation in boiler is controlled by____________________?

A. Preheating of feed water
B. Reduction in hardness, silica & alumina in feed water
C. Keeping the pH value of feed water just below 7
D. Eliminating H2S in feed water

Main pollutant present in automobile exhaust is_________________?

A. CO
B. CO2
C. NO
D. Hydrocarbons

Pollution by particulate matter emission in the atmosphere does not take place during metal____________________?

A. Grinding
B. Machining
C. Cutting
D. Polishing

Arsenic pollutant is not generated in _______________ industries?

A. Tanneries
B. Glass & ceramic
C. Beverages
D. Any of these

The pH value of oxidised sewage is about_____________________?

A. 1.8
B. 6.2
C. 7.3
D. 13.4

Growth of ______________ is promoted by the presence of manganese in water?

A. Files
B. Algae
C. Micro-organisms
D. Mosquitoes

Presence of nitrogen in high concentration in contaminated air reduces partial pressure of oxygen in lungs, thereby causing asphyxia (suffocation) leading to death from oxygen deficiency. Concentration of N2 in contaminated air at which it acts as a natural asphyxiate is ≥ _____________ percent?

A. 84
B. 88
C. 80
D. 92

Radioactive solid nuclear wastes are disposed off by _________________?

A. High temperature incineration
B. Pathological incineration
C. Pyrolysis
D. Underground burial in concrete containers

Which of the following is an adsorbent used for the removal of SO2 from gas/air ?

A. Bog iron
B. Limestone powder or alkalised alumina
C. Silica gel
D. Active carbon

‘Safe limit’ called Threshold Limit Value (TLV) of carbon monoxide in atmospheric air is < 50 ppm. The main source of carbon monoxide pollutant in air is the____________________?

A. Industrial chimney exhaust
B. Automobiles exhaust
C. Photochemical reaction in polluted atmosphere
D. Burning of domestic fuel