Correct option (b) ΔG/ΔH
Explanation :
The thermal efficiency, n of a fuel conversion device is the amount of useful energy produced relative to the change in enthalpy, ΔH between the product and feed streams.
In an ideal case of an electrochemical converter, such as a fuel cell, the change in Gibb's free energy, ΔG of the reaction is available as useful electric energy at that temperature of the conversion.
