2. Reversible & Irreversible Reactions
Reversible Reaction : It A Type Of Reaction In
Which Reactants Are Completely Converted In To The
Product & Product Is Also Converted In To The
Reactants .
For Example :
Dissociation Of Hydrogen iodide .
2HI H2 + I2
It is Denoted By Two Parallel Arrows .
3. Irreversible Reaction : Is A Type Of Reaction In
Which Reactant Converted In To The Product But
Reverse Is Not Possible .
For Example :
Nacl + Ag NO3 NaNO3 + AgCl
It Is Denoted By Single Arrow .
4. Equilibrium State
The State Comes During The Reversible Reaction At
Which Rate Of Forward Reaction Is Equal To The Rate
Of Backward Reaction .
In The Beginning , Forward Reaction Predominates ,
But As Soon As Product Is Formed , The Reverse
Reaction Starts Until Equilibrium Position Is
Reached. Where Rate Of Forward And Backward
Reaction Is Same .
5. The Law Of Mass Action
• It Is Stated That : The Rate At Which A Substance
Reacts Is Proportional To Its Active Mass
(Concentration) And The Rate Of A Chemical
Reaction Is Proportional To The Product Of The Active
Masses Of Reactants .
6. Factors Affecting The Chemical
Equilibrium
1. Effects Of Conc: Change :- By Increasing The
Concentration Of Any Substance Present In The
Equilibrium Mixture, The Balance Is Disturbed ,
And The Equilibrium Moves away From That
Substance .
7. Increase In Conc. Of
Reactants.
Increase In Conc. Of
Products .
Equilibrium Shifts To
Right and Product
Increases .
Equilibrium Shifts To
Left and More Reactant
Formed .
8. Effects Of Temperature Change
• In Exothermic Reaction ,Increase In Temperature
Will Shift Equilibrium Towards Left & Decrease In
Temperature Will Shift Equilibrium Towards Right .
• In Endothermic Reactions , Increase In
Temperature Will Shift Equilibrium Towards Right &
Decrease In Temperature Will Shift Equilibrium
Towards Left .
9. Effects Of Pressure Change
If Volume Of Reactants Is Greater Then Products,
Increase In Pressure Will Shift Equilibrium Towards
Right & Decrease In Pressure Will Shift Equilibrium
Towards Left.
If Volume Of Products Is Greater Then Reactants ,
Increase In Pressure Will Shift Equilibrium Towards
Left & Decrease In Pressure Towards Right .
10. Effects Of Catalyst
A Catalyst Enables Equilibrium To Be Reached More
Quickly . A Catalyst Affects Forward And Reverse
Rates Equally .
