6888. One mole of methane undergoes complete combustion in a stoichiometric amount of air. The reaction proceeds as CH₄ + 2O₂ → CO₂ + 2H₂O. Both the reactants and products are in gas phase. ΔH°298 = – 730 kJ/mole of methane. If the average specific heat of all the gases/vapour is 40 J/mole.K, the maximum temperature rise of the exhaust gases in °C would be approximately equal to