Anaerobic bacteria digest animal waste and produce biogas (Change – A).
The biogas is then burnt as fuel (Change – B). The following statements pertain to these changes. Choose the correct one.
- Process – A is a chemical change.
- Process – B is a chemical change.
- Both processes A and B are chemical changes.
- None of these processes is a chemical change.
- Digestion of animal waste results in the production of biogas ( a new substance).
- Biogas being burnt as fuel is accompanied by the evolution of heat and energy .
- Since neither of them can be reversed , both are chemical changes .
So, the correct answer is (iii) .