aromatic ring, which lies between 6.0 and 8.5 ppm. It is also worthwhile to know the general ranges
for hydrogens on sp^3 -hybridized carbons (0.0 to 3.0 ppm; higher if electron-withdrawing groups are
present), sp^2 -hybridized carbons (4.6 to 6.0 ppm), and sp-hybridized carbons (2.0 to 3.0 ppm). When
electronegative groups are present, they pull electron density away from the protons. The more
electron density that is pulled away from the proton, the more deshielded it will be and the further
downfield the proton will appear.
Table 11.3. Proton Chemical Shift Ranges
Type of Proton Approximate Chemical Shift δ (ppm) Downfield from TMS
RCH 3 0.9
R 2 CH 2 1.25
R 3 CH 1.5
RC=CH 4.6–6.0
RC≡CH 2.0–3.0
Ar–H 6.0–8.5
RCHX 2.0–4.5
RCHOH/RCHOR 3.4–4.0
RCHO 9.0–10.0
RCOCH 3 2.0–2.5
RCHCOOH/RCHCOOR 2.0–2.6
ROH 1.0–5.5
ArOH 4.0–12.0
RCOOH 10.5–12.0
RNH 2 1.0–5.0MCAT EXPERTISE
On Test Day, just counting the number of peaks and unique hydrogens may be enough to get
you the correct answer. (Remember not to count the peak for TMS, though!) If you need to