Which of the following will increase the number of collisions and energy of reactant molecules?

adding a catalyst
increasing the concentration of reactants
increasing the pressure of the reactant mixture
increasing the temperature of the reactant mixture

increasing the temperature of the reactant mixture

Explanation:

According to the collision theory , the number of collisions that take place per unit volume of the reaction mixture is called collision frequency. The effective collisions are ones which result into the formation of products.  

It depends on energy factor: For collision to be effective, the colliding molecules must have energy more than a particular value called as threshold energy.  

Thus increasing the temperature of the reactant mixture, the reactant molecules will gain kinetic energy and thus will increase the number of effective collisions.

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