(a) (i) Whataregalvaniccells? (ii) Write any two advantages of fuel cells. (b) Write the electrode reactions is H2 – O2 fuel cells.

Question

Fuel cells are special types of galvanic cells. 

(a) (i) Whataregalvaniccells?

(ii) Write any two advantages of fuel cells.

(b) Write the electrode reactions is H₂ – O₂ fuel cells.

Answer 1

(a) (i) These are devices for converting chemical energy into electrical energy. The decrease in free energy in a spontaneous chemical process appears as electrical energy. e.g., Daniell oeil.
(ii) (1) Fuel cells are pollution free.

(2) Fuel cells are highly efficient (about 70%) compared to thermal plants (about 40%)

(3) Fuel cells run continuously as long as the reactants are supplied. 

(b) At cathode:

O₂(g) + 2H₂O(l) + 4e → 4OH(aq)

At anode:

2H₂(g) + 4OH(aq) → 4H₂O(l)