Speeding up chemical reaction

For the acidified potassium permangante, the sulphuric acid is rather a reactant then a catalyst. It is beacuse when the acidified potassium permangante is oxidizing a reducing agent like an alcohol, the hydrogen ions from the sulphuric acid is consumed. Therefore it cannot regard as catalyst in this case.

Equation:MnO4-(aq) + 8H+(aq) + 5e- --------> Mn2+(aq) +4H2O(l)

While for the alkenes, the substitution reaction is not the typical reaction for alkenes. Usually alkene will undergo addition reaction. The sulphuric acid can act as a catalyst some addition reaction of alkene such as hydration of alkene to alcohol, Is the beacuse the hrdrogen ions from sulphuric acid can protonate the alkene to give a carbonium ion. The postitively-charged carbonium ion formed is more easily being attacted by the water molecules to give the alcohol.

Heating can speed up reaction rate beacuse for the molecules can react, the molecules need to have enough energy to overcome the energy barrier (acitvation energy). Upon heating, more molecules in the reactant can have sufficient energy to overcome the energy barrier hence the reaction can speed up.