Select the correct answer from the choice A, B, C given in each case.

1. The major pollutant released during burning of fossil fuels.
   A: Carbon monoxide B: Sulphur dioxide C: Hydrogen sulphide

2. The green house gas which on combustion produces another green house gas.
   A: Nitrous oxide B: Ozone C: Methane

3. The gas which in presence of U.V. light gives two atoms of the same gas.
   A: Oxygen B: Ozone C: Carbon dioxide

4. A chemical responsible for ozone depletion.
   A: Methyl acetylene B: Methyl chloride C: Methanol

5. A renewable source of energy which causes minimum or no pollution.
   A: Fossil fuel B: L.P.G. C: Hydro power.

Give balanced equations for the following conversions [one or two steps].

1. Sulphur trioxide to sulphuric acid – a constituent of acid rain.
2. Nitrogen to nitrogen dioxide – in an internal combustion engine.
3. Methane to carbon dioxide – a green house gas.
4. A molecule of ozone to two molecules of oxygen gas.
5. Oxygen to ozone gas by photolysis.

Give reasons for the following.

A catalytic converter in an internal combustion engine reduces pollution.

Give reasons for the following.

In absence of green house gases the surface temperature of the earth is maintained.