09 The product obtained by destructive distillation of coal is 1. coke 2. coal tar 3. coal gas 4. all of these

11 The green house effect is due to an excessive emission of this gas 1. sulphur dioxide 2. nitrogen dioxide 3. phosphorous trioxide 4. carbon dioxide

13 The least polluted fuel is 1. petrol 2. kerosene oil 3. coal 4. CNG