What is activation energy in a chemical reaction and what happens when we provide activation energy to a chemical?I know it's going to react.But I need to know the full procedure.And why activation energy is different from bond energy?

Activation Energy and Bond energy

Activation energy is the energy required for any molecule to take part or initiate the reaction.

Bond energy is the energy given out or taken in when the bond between molecules or atoms are split.

Activation energy is required for all reactions to proceed naturally. All reactions require this. This is supplied from the surroundings at normal and temperature when the reacting species are reactive or active enough. (e.g.) Corrosion of iron. Oxygen in air and water are reactive enough to react with Iron to form Ferrous or Ferric oxide.

Otherwise activation energy is supplied through external means such as Pressure, Temperature, Catalyst, enzyme, light etc. There are quite a lot of examples that can be stated to this statement.

Burning of any fuel is such an example where the reaction takes the activation energy in terms of heat energy. LPG burns in air when it has a critical concentration and some ignition source which gives enough activation energy for the reaction to proceed. Wood needs a little more energy compared to gaseous and liquid fuels to burn. It needs a sustained heat energy for the surface molecules to burn then the reaction is sustained by itself.

Chemical manufacture of most chemical require activation energy in terms of Pressure and catalyst. The catalyst provides an alternate path for the reaction to initiate. But the pressure and thermal energy directly supply the required activation energy.

The manufacture of ammonia is such an example. There is plenty of Nitrogen in atmosphere and trace amounts of pure Hydrogen. They don't react because the molecules are quite stable and non reactive at NTP. But when they are pressurized in presence of catalyst they react to give Ammonia.

Bond energy is the energy that generally comes out because of splitting the bond between atoms and or or molecules. This can also be felt from the burning of fuels. The oxygen splits the bond between Carbon and Hydrogen in LPG and the energy is let out as heat.