The term Hydrogen Economy coined by Bockris in 1970 proposes a system of delivering energy using hydrogen. (a) Illustrate how hydrogen can be generated from natural gas. Your answer should include the chemical reactions and/or schemes as appropriate. (b) The generation of hydrogen from natural gas is not sustainable in the long term due to the emissions of carbon dioxide. Discuss alternative methods for producing hydrogen on a sustainable basis. Your answer should include chemical reactions and/or schemes as appropriate. (c) Hydrogen generated as in the previous sections must undergo purification before utilization in fuel cells. Describe the methods of purification of hydrogen. Use diagrams/schemes as appropriate.