If you mixed water and dilute sulfuric acid, rather than concentrated sulfuric acid, would the exothermic reaction be greater or less than the exothermic reaction that occurs during hydration of a concentrated sulfuric acid? If so, why?

Answer 1

Less if you mix water and dilute H2SO4 because some of the energy has already been emitted. See my later post about the dangers of adding water to conc H2SO4.