Degree of unsaturation is the no of H2 moleules required by the molecule 2 become saturated.
Ex: C2H4 : Ethene .
requires one molecule of H2 to become saturated .so DU =1 .
Ex :
cyclopropane has the formula C3H6.
IT REQUIRES 2 H TO become saturated. So. DU = 1 .
Cyclopropene has the fromula C3H4.
There is double bond as wel as aring , so it needs 2 molecules of H2 i.e. 4 H atoms , to become saturated.
Formula 4 DU = {( 2C + 2 ) + N + P - H -X } / 2
N - no of Nitrogen atom
P - no of phophorous toms.
H - no of H atoms .
X -no of halogens.
C -no of carbons.