Solution
Let us start with the easiest part, the signal
at about 1.6 ppm.
C
4
H
10
O measured in CDCl
3
The sample is measured in CDCl
3
. Typically, two
proton signals are found in CDCl
3
, although this is
not at all to be expected from the molecular
formula CDCl
3
.
First, there is a signal from CHCl
3
at about 7.25 ppm. This is due
to the non-100% deuteration and is therefore often referred to
as the "residual proton signal". In this example, the signal is
outside the spectral range shown.
On the other hand, deuterated solvents nearly always contain a small
amount of water as an impurity. In CDCl
3
, its signal appears at about 1.6
ppm.
With high probability, HOD is present.
HOD