The expanded form of DDT is

1. dichloro diphenyl trichloroethane

2. dichloro diethyl trichloroethane

3. dichloro dipyridyl trichloroethane

4. dichloro diphenyl tetrachloroacetate

Q. 8 Which of the following material takes the longest time for biodegradation?

1. Cotton

2. Paper

3. Bone

4. Jute

Choose the incorrect statement :

1. The Montreal protocol is associated with the control of emission of ozone-depleting substances

2. Methane and carbon dioxide are greenhouse gases

3. Dobson units are used to measure the oxygen content

4. Use of incinerators is crucial to the disposal of hospital waste

Q.10 Among the following which one causes more indoor chemical pollution?

1. Burning coal

2. Burning mosquito coil

3. Burning cooking gas

4. Room spray

The green scum seen in the freshwater bodies is

1. blue-green algae

2. red algae

3. green algae

4. Both (a) and (c)

Q.12 The loudness of a sound that a person can withstand without discomfort
is about

1. 150 dB

2. 215 dB

3. 30 dB

4. 80 dB

Q.13 The major source of noise pollution, worldwide is due to

1. office equipment

2. transport system

3.sugar, textile, and paper industries

4. oil refineries and thermal power plants

Match correctly the following and choose the correct option :

The correct matches are

Q.15 Catalytic converters are fitted into automobiles to reduce the emission of harmful gases. Catalytic converters change unburnt hydrocarbons into

1. carbon dioxide and water

2. carbon mono oxide

3. methane

4. carbon dioxide and methane

Why is it necessary to remove sulfur from petroleum products?