Hi, Alok. If you're wondering whether you can stack different-model switches together, the answer is yes. The following tables will tell you which switch models can be stacked with each other, and the stacking methods to use in each case.
For switches that run EXOS version 16, use 
this table.
For switches that run EXOS version 21 & 22, use 
this table.
Larry Kunz
Extreme Networks 
Information Development