Question

A vessel contain a non linear triatomic gas.if 50% of gas dissociate into individual atom,then find new value of degree of freedom

Answer 1

Let's assume that we have 1 mole of triatomic gas. 
Therefore 3Na (Avogardo's Number) is present initially.
So, 0.5 moles has 1.5Na atoms.
Now, 1 part of 0.5 moles remains undissociated.
So. degree of dissociation = 0.5 x 6 = 3
The other 0.5 moles has 1.5Na which breaks into 3 atoms.
So, total number of atoms = 0.5Na
Now, degree of freedom for monoatomic gas = 3
So, degree of freedom for 0.5Na monoatomic particles = 1.5 x 0.5 = 0.75
Hence, total will be 3 + 0.73 = 3.75
which is the required answer.
Thanks.

Answer 2

degree of fredo of 0.5 mole of triatomic gas . which is

undissociated = .05*6=3(6=degree of fredom of  non linear triatomic gas )      

degree of dissociated gas = 0.5/2*3=0.75(3=degree of f..of dissociated gas )

hence total degree of fredom =3+0.75=3.75