Mark the statements as true (T) or false (F)

i) An electrostatic precipitator removes particulate matter by imposing positive charge on them.
ii) Catalytic converters convert unburnt hydrocarbons into CO₂ and water.
iii) DDT is a non biodegradable secondary pollutant.

i- F
ii- T
iii- F

The correct answer is Option (2)-

i- F
ii- T
iii- F

An electrostatic precipitator removes particulate matter by imposing negative charge on them. Electrostatic precipitators are very efficient devices that can remove 99% of particulates present in the industrial and thermal plant exhausts. There are electrode wires and a stage of collecting plates. The collecting plates are connected with ground. The electrode wires are provided with several thousand volts of electric current. It creates a corona which releases electrons. The electrons attach to the suspended particles and make them negatively charged within a fraction of second. Air with charged particles passes slowly over collecting plates . The particulate matter settles over them and are removed.
Catalytic converters convert unburnt hydrocarbons into CO₂ and water.
DDT is a non biodegradable primary pollutant.