What are the advantages of using hydrogen as fuel?

Explanation

(i) `H_2` has high energy per unit weight of fuel.
(ii) Burning of `H_2` will not release any pollutants.
(iii) On combusion it forms water as a byproduct.
(iv) Fuel Cells which use `H_2` as fuel shows 70 to 80% higher efficiency than other fuel cells.