Hint 9-41

The multiplicity means how complex the ¹H NMR signal we are considering will be when spin-spin splitting is observed.

The rule for predicting spin-spin splitting (coupling) is:
the multiplicity of the signal = n + 1, where n is the number of chemically equivalent Hs in the adjacent group(s).
The adjacent groups refers to Hs that £ 3 bonds away from the Hs being considered.

You start by drawing out the molecule with all Hs shown.

Singlet = no Hs adjacent Doublet = 1 H adjacent Triplet = 2Hs adjacent

Quartet = 3Hs adjacent Pentet = 4Hs adjacent Sextet = 5 Hs adjacent
Septet = 6Hs adjacent