Consider a tubular reactor, in which a first order exothermic chemical reaction (AB) is taking place. We assume that there are no radial temperature, velocity or density gradients. Temperature of the mixture in the reactor, however, is changing with the axial position. The reactor has a cooling jacket through which water is circulated. Heat can be transferred from the process fluid consisting of reactants and products at temperature T to the walls of the reactor at temperature Tw and from walls to the cooling water. Derive a mathematical equation, which describes the temperature distribution