Question

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.