1
An electrochemical cell is fueled by the combustion of butane at 1 bar and 298 K. Its cell potential is XF 103 volts, where F is the Faraday constant. The value of X is . Use: Standard Gibbs energies of formation at 298 K are: f GoCO2 = -394 kJ mol-1; f Gowater = -237 kJ mol-1; f Gobutane = -18 kJ mol-1
Answer
105.4 to 105.6
Solution
C4H10 + 132O2 4CO2 + 5H2O
r Go = 4(-394) + 5(-237) - (-18) = -2743 kJ mol-1
Electrons transferred: 132 O2 4 = 26 (C: - 52 +4, 4 6.5 = 26)
Eo = - GonF = 2743 10326F = 105.5F 103 V
Answer: 105.5
JEE Advanced 2025 Paper 2