Effects of pressure change on equilibrium

When the forward and reverse reactions occur at equal rates then this system is called chemical equilibrium.

A+B ↔ C+D

2. Presented by
•Masud Rana
•MohsinMia
•DebabrataOjha
•FiroseMahamud

3. WE PRESENTED
Effects of Pressure Change on
Equilibrium

4. CHEMICAL EQUILIBRIUM
•When the forward and reverse reactions occur at equal
rates then this system is called chemical equilibrium.
A+B ↔ C+D

5. LE -CHATELIER’S PRINCIPLE
Principle: “when a stress is applied on a system is
equilibrium, the system tends to adjust itself so as to
reduce the tress”
There are three ways in which the stress can be caused on
a chemical equilibrium.
1.Changing the concentration of the product
2.Changing the pressure of the system
3.Changing the temperature

7. •When pressure is increased on a gaseous
equilibrium reaction, the equilibrium will shift
in a direction which tends to decrease the
pressure.
Effects of Pressure
Change on Equilibrium

8. 2SO2(g) + O2(g) ↔2SO3(g)
When we increase pressure equilibrium shift on right
2SO2(g) + O2(g) + increase pressure↔ 2SO3(g)
Equilibrium shift
Let us consider a reaction→

9. Again if we decrease pressure then equilibrium shift on
left
2SO2(g) + O2(g) + increase pressure↔ 2SO3(g)
Equilibrium shift

10. Again if we consider this reaction
←Pressure increase, shift Right to Left
PCl5(g) ↔ PCl3(g) + Cl2(g) + Pressure increase
Pressure Decrease, shift Left to Right→

11. But Reactions not affected by pressure
changes when number of molecules are same
in both side.
H2(g) + Cl2(g) ↔ 2HCl(g)
CO(g) + H2O(g) ↔ CO2+ H2

12. SOME EXAMPLE
SYSTEM PRESSUR
INCREASE
PRESSUR
DECREASE
N2O4=2NO2
← →
PCl5=PCl3+Cl2
← →
2SO2+O2=2SO3
→ ←
N2+3H2=2NH3
→ ←
N2+O2=2NO
No effect No effect