1. The activation energy for an electron transfer reaction does not directly vary with temperature. However, the rate at which the reaction occurs is affected by temperature. According to the Arrhenius equation, the rate constant k of a reaction is related to the activation energy Ea and temperature T as follows:k = Ae^-Ea/RT where A is the pre-exponential factor, R is the gas constant, and T is the temperature in Kelvin. As the temperature increases, the rate constant k increases, meaning the reaction occurs at a faster rate. This is because, at higher temperatures, more molecules have sufficient energy to overcome the activation energy barrier, leading to an increased probability of successful collisions and electron transfer.2. The relationship between the rate constant k and the activation energy Ea of a redox reaction is given by the Arrhenius equation mentioned above. The rate constant is directly proportional to the exponential of the negative activation energy divided by the product of the gas constant and temperature. A higher activation energy corresponds to a slower reaction rate, while a lower activation energy corresponds to a faster reaction rate.3. To predict the direction of electron transfer in a redox reaction, we can use the reduction potential E values of the half-reactions involved. The reduction potential is a measure of the tendency of a chemical species to gain electrons and undergo reduction. In a redox reaction, the species with a higher reduction potential will undergo reduction gain electrons , while the species with a lower reduction potential will undergo oxidation lose electrons . The overall redox reaction will proceed spontaneously if the difference in reduction potentials E is positive, as this corresponds to a negative change in Gibbs free energy G and a thermodynamically favorable reaction.