Advices For Studying Organic Chemistry

4. Calculating the index of Hydrogen Deficiency (IHD):
   
   
   1. For compounds containing halogen atoms: simply count the halogen atoms as
      hydrogen atoms.
      C 4 H 6 Cl 2 = C 4 H 8 ⇒ IHD = 1
   
   
   2. For compounds containing oxygen atoms: ignore the oxygen atoms and
      calculate the IHD from the remainder of the formula.
      C 4 H 8 O = C 4 H 8 ⇒ IHD = 1
   
   
   
   

CH 2 =CHCH 2 CH 2 OH CH 3 CH 2 =CHCH 2 OH CH^3 CH^2 CCH^3

O

CH 3 CH 2 CH 2 CH

O

O

O

and so on

CH (^3)
3) For compounds containing nitrogen atoms: subtract one hydrogen for each
nitrogen atom, and then ignore the nitrogen atoms.
C 4 H 9 N = C 4 H 8 ⇒ IHD = 1
CH 2 =CHCH 2 CH 2 NH 2 CH 3 CH 2 =CHCH 2 NH 2 CH^3 CH^2 CCH^3
NH
CH 3 CH 2 CH 2 CH
NH
N H
N
H CH 3
and so on