Chemical Reaction Engineering | Types of Reactions | GATE

• Homogenous Reactions:

The reaction which is carried out in only one phase is called a homogenous reaction.

• Heterogenous Reactions:

The reaction which is carried out in more than one phase is known as heterogenous reaction.

• Reaction Rate :

The reaction rate can be defined on the basis of:

1. Volume of reacting fluid:

2. Unit of mass fluid :

3. Volume of reactor :

4. Surface of solid :

5. Volume of solid:

Reaction rate is dependent upon the rate of system i.e. :

• temperature,
• pressure and
• composition.

Types of Reactions:

• Single Reaction : When a single stoichiometric reaction and single rate equation is selected to represent the progress of reaction, it is called a single reaction.
• Multiple Reaction : When more than one stoichiometric equation are used to represent the progress of reaction, it is called a multiple reaction.

Types of multiple reactions:

i. Series Reaction : 

ii. Parallel Reaction :

(a) Competitive reaction

(b) Side by side reaction

(c) Parallel but in series

Elementary Reaction:

The reaction in which rate depends upon stoichiometry of the reaction is called an elementary reaction.

e.g.

Non-elementary reaction :

The reaction in which rate does not depend upon stoichiometry of the reaction is called an non-elementary reaction.

e.g.

Forward Reaction:

If the reactant in the reaction is formed or produced the reaction is called a forward reaction.

Reverse Reaction:

If the reactant in the reaction is disappearing the reaction is called a reverse reaction.

e.g.

Here: is rate of forward reaction and – is the rate of reverse reaction written respectively as :

It is important to remember that :

Chain Reaction:

1. Reaction Initiation :

2. Reaction Propogation :

3. Reaction Termination :

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