If, we discharge the electrochemical cell rapidly, then :
The cell will give out maximum entropy
The question contrasts a rapid discharge with a slow one, and the whole answer follows from the difference between reversible and irreversible operation.
A cell delivers its maximum electrical work only when discharged reversibly — infinitely slowly, against an opposing potential just short of the cell emf. In that limit the useful work equals the Gibbs free energy change, \(w_{elec} = \Delta G = -nFE\), and no entropy is generated internally.
Discharging rapidly is strongly irreversible. Large currents flow, and with them come several dissipative losses: ohmic (IR) drop through the electrolyte, activation overpotential at the electrode surfaces, and concentration polarisation as ions cannot diffuse fast enough to keep up. Each of these degrades free energy into heat.
The thermodynamic statement of this is that irreversible processes generate entropy: \(\Delta S_{universe} > 0\), and the faster and further from equilibrium the process, the more entropy is produced. So a rapid discharge produces the maximum entropy.
The other options are each the reverse of this. "Maximum enthalpy converted to useful work" is wrong twice over — the theoretical limit on useful work is \(\Delta G\), not \(\Delta H\), and rapid discharge falls short of even that. "Small amount of entropy generated" describes the slow, near-reversible case. And "maximum energy density" is wrong because the measured cell voltage sags under heavy load, so less energy is extracted before the cutoff voltage is reached — the familiar observation that a battery drained quickly delivers less total energy, and gets hot doing it.
Hence rapid discharge means the cell gives out maximum entropy.
Similar Questions
The property measured in derivative thermogravimetric analysis (DTG) is :
Analysis of four different samples of an alloy yielded 12.12, 12.14, 12.10 and 12.22% of metal. The mean deviation of the result is :
For the first order consecutive reaction :
Which of the following statement is incorrect ?
A given reaction is fitted into the following Arrhenius form :
K2 = 6.0 × 1014 (S-1) . exp \(\left[-\frac{104.4\ (\mathrm{kJ\,mol^{-1}})}{RT}\right]\)
Value of the rate constant at very high temperature would be :
E° value for various ions are as follows :
E°(MnO4-) = +1.51 V
E°(Ag/Ag+) = +0.7996 V
E°(Au/Au+) = +1.692 V
E°(Zn/Zn2+) = -0.761 V
Based on this data, permaganate can be used to oxidize :
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(Given : vapour pressure of pure organic solvent is 100 torr; the molecular weight of organic solvent is 100 g mol-1).
The following half cell represents, normal hydrogen electrode (NHE) :
Consider the reaction :
H2S(g) + \(\tfrac{3}{2}\) O2(g) → SO2(g) + H2O(g), ΔH° = 518.62 kJ
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Important Questions from Thermodynamics
- Second law of thermodynamics states that
A. Energy flows from higher concentration to lower concentration.
B. Order becomes disorder during energy transformations.
C. The quality of energy degrades as it is transformed.
D. Degraded energy is entropy, dessipated as waste products or heat.
E. Enthalpy is wasted in energy transformation.
Choose the most appropriate answer from the options given below: Choose the Incorrect Statement:
1 For a system at equilibrium, chemical potential is same in all phases.
2 Gibb's free energy change is zero at equilibrium state of a system.
3 Gibb's free energy change is positive for reaction to occur spontaneously.
4 $\Delta G$ will become more negative with increasing temperature.- In a closed thermodynamic system, across its boundaries
- The first law of thermodynamics states about
Melting Point of pure ice is-
