Plzz answer ques. 10 as soon as possibleAnsis 2Img is attached

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