Adsorption and Degree of Unsaturation - Practice Questions & MCQ

Adsorption
The phenomenon of the deposition of particles on the surface of the adsorbent is called adsorption. 

For example, the rate of adsorption among the following molecules is higher for cyclopentene.

   Cyclopentene     Cyclohexene

Since the size of cyclopentene is smaller than cyclohexene, thus the rate of adsorption is higher for cyclopentene than cyclohexene.

Occlusion
The adsorption of hydrogen on the surface of the noble metals is known as occlusion. These noble metals can be Platinum or Palladium.

Degree of Unsaturation
It is the calculation to analyse the total number of double bonds and rings in the organic compound. It is also known as index of hydrogen deficiency or unsaturation index.

• The degree of unsaturation for simple compounds like benzene is given as:
  Degree of unsaturation = Number of pi bonds + Number of rings
  Thus, Degree of unsaturation = 3 + 1 = 4   (Since there are 3 double bonds in benzene ring and 1 ring is only present)
• For complex compounds like C₁₀H₆N₄, the degree of unsaturation is given as follows:
  These complex compounds can be represented as C_xH_yN_zO_pX_q. Now, the degree of unsaturation for complex compounds are given using the following formula:
  

Where, C is the number of Carbon atoms, H is the number of Hydrogen atoms, N is the number of Nitrogen atoms and X is the number of Halogen atoms. It is to be noted that  the Oxygen atoms have no bearing on the degree of unsaturation

Now for the compound C₁₀H₆N₄ we have, x = 10, y = 6 and z = 4
Thus, degree of unsaturation = (10 + 1) - (6 + 0 - 4)/2
Degree of unsaturation = 10