<prompt> Among the following, the maximum redox potential is forNADHNADSuccinyl Co A fumarateUbiquinoneFe 2  <response>: Redox potentials of redox couples Cyt a3 Fe2 Cyt a3 Fe30.386 REDOX POTENTIAL AND FREE ENERGY In the discussion so far, we have made it clear that an oxidising or reducing agent may exist in two forms, a the oxidised form or oxidant which can accept electrons and b the reductant which can donate its electrons to a substrate. Each oxidizing or reducing agent exists as a conjugate pair of electron acceptor oxidant and electron donor reductant forms. Where n is the number of electrons. The pair consisting of the oxidant and reductant forms of an oxidizing or reducing agent is known as a redox couple or conjugate redox pair, e.g. NADNADH, FMNFMNH2, Cyt-c FeCyt-c Fe. Oxidising agents differ in their electron affinity. The standard redox potential Eo is a measure of the tendency of a redox couple to donate or accept electrons under standard conditions. The redox potential of a given system is intimately related to its free energy change. If redox-potential of a given system is known, the corresponding free energy change which might occur in the system on oxidation or reduction may be found as follows: DF -nfDEo Coulomb Joules Where F Standard free energy n no. of electrons f Faradays constant 96,500 Coulombs DEo Difference between redox potentials of the couple. nfDEo orDF ___ calories 4.18 If the sign of free-energy thus calculated is negative, it indicates free energy release and if positive, it indicates free energy consumptionRef: MN Chatterjea Textbook of Medical Biochemistry, 8th Edition, Page no: 138 