Question

Q 9.3: how many triplets would you expect to observe in the 1h nmr spectra for o-chlorotoluene

Answer 1

No triplet.

Step-by-step explanation:

A triplet is observed in proton nmr when the neighboring, chemically non equivalent, carbon atoms bear two hydrogen atoms.

Let us examine the structure of o-chlorotoluene [shown in figure].

As shown in the figure there is no carbon bearing two equivalent hydrogen.

There are five non equivalent kind of hydrogen on the molecule

Three hydrogen are equivalent (Ha)

So we will observe only

a) Singlet

b) Doublet

c) Double doublet (split doublet)

Answer 2

Hello!

You would expect to observe 2 triplets in the ¹H NMR spectra for o-chlorotoluene.

Multiplicity observed in ¹H NMR spectra when the atom couples with a neighbor ¹H atom. The multiplicity is equal to N+1 where N is the number of neighbor atoms.

To observe a triplet, you'll need a molecule with 2 neighbor atoms. In o-chlorotoluene (shown in the figure), only protons C and D have 2 neighbor atoms (B and D; A and C, respectively), so you'll expect to see a 2 triplets.

Have a nice day!