What are fuel cells? How do they resemble and differ from galvanic cells?
Solution
Fuel cells are galvanic cells that convert the energy of combustion of a fuel (H, CH, CHOH) directly into electrical energy, the fuel and oxidant being supplied continuously from outside.
Resemblance: like any galvanic cell, they produce electricity from a spontaneous redox reaction occurring at two electrodes connected through an electrolyte.
Difference: an ordinary galvanic cell stores its reactants and becomes dead when they are used up, whereas a fuel cell works continuously as long as fuel and O are supplied — it never becomes dead and its electrodes only catalyse the reaction.
Resemblance: like any galvanic cell, they produce electricity from a spontaneous redox reaction occurring at two electrodes connected through an electrolyte.
Difference: an ordinary galvanic cell stores its reactants and becomes dead when they are used up, whereas a fuel cell works continuously as long as fuel and O are supplied — it never becomes dead and its electrodes only catalyse the reaction.
CBSE Class 12 Board · 2005 · Foreign · Subjective