At 35C which is the lowest temperature in this experiment, the time taken for the permanganate to decolourize is 77 seconds. At 60C which is the highest temperature in this experiment , the time taken for the permanganate to decolourize is 13 seconds. From the reaction above, the changes from permanganate ion, MnO4- to Manganese ion, Mn2+ involved bond breaking under oxalic acid. Energy is required through this process. The energy produced by colliding molecules is not sufficient. However, they must collide with sufficient energy to overcome the energy barrier which is activation energy. When the temperature increases, the number of collisions between reactant molecules increases, the energy of the collision increases. In this case, the collisions between reactant molecules may have sufficient energy to overcome the barrier. Therefore, the reaction rate decreases when temperature increasing.