Question

What is activation energy and how catalyst speed up the reaction by decreasing activation energy. Don't just tell me definition but explain its concept by visualisation.

Answer 1

Well, it lowers the activation energy by offering a faster and alternative pathway for the reaction to happen.

Answer 2

Activation energy is the minimum energy required in order to undergo a reaction. (Well the definition may vary slightly )

Answer 3

A catalyst increases the rate of a reaction. However it is not used up in the reaction. So it's final concentration is the same as the initial concentration. Sometimes, the catalyst engages in the chemical reaction whereas in other cases it only provides the substrate for the reaction where it absorbs the reactant molecules on to the surface.
The activated complex formed when the reaction is catalyzed is different from the activated complex formed when the reaction is uncatalyzed. That is the reaction occurs via a new mechanism. Then the activation energy of the reaction is reduced thereby causing its rate to increase. But remember it doesn't increase the amount of products formed. It only increases the rate wt which products are formed.
Example
Imagine 2 moles of x compound was formed during 7 mins when a uncatalyzed. When u catalyze the reaction 2 moles of X compound will be formed during 4 mins. That's difference there. It never increases the amount of products.

Answer 4

Okay now I understand but what do you mean by that the catalyst speed up the reaction by changing reaction pathway. Can you please explain the difference between pathway of catalysed and uncatalysed reaction.