Paper: CSIR-NET December 2012 · Subject: Physical Chemistry · Chapter: Chemical Kinetics · Topic: Chemical Kinetics – General · Marks: 2 · Difficulty: Medium
A chemical reaction involving nonlinear molecule + nonlinear molecule ⇋nonlinear activated complex .The number of vibrational degrees of freedom in the activated complex, containing N atoms, is
(a)3N-5
(b)3N-6
(c)3N-7
(d)3N-8
Answer
Answer: C ✓ checked by 4AB · confidence high
The source book printed no answer; this one was worked out and checked — see the explanation.
Explanation
A non-linear N-atom complex has 3N − 6 vibrations, but one of them is the reaction coordinate (treated as a translation), leaving 3N − 7 genuine vibrations.