Question

What is the correct increasing order of stretching frequencies for C ≡ C, C = C and C — C? *

Answer 1

In increasing order of the stretching frequency  the carbon bonds are given  C ≡ C> C = C > C — C

Explanation:

• the stretching frequency increases with increase in the number of Pi bond which is present in the carbon bond. In case of triple bond there are two pi bond , in case of double bond there is only a single pi bond.
• This is because with increase in the number of bond there is decrease in the atomic distance and hence there is more chance of stretching between the two atoms with respect to each other

Answer 2

Answer:

Since, v ∝ √k , k→ Force constant. Force constant trend is

Triple bond > Double bond > Single bond.

C ≡ C > C = C > C — C.