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Spectroscopy practice

Spectrum-to-molecule practice

These initial exercises use clearly labeled simulated educational evidence.

Carbonyl solvent

C3H6O

DBE 1; strong IR near 1715 cm−1; singlet integrating to 6H.

Progressive hints
  1. Calculate DBE: one ring or pi bond.
  2. A strong 1715 cm−1 band supports a carbonyl.
  3. One proton environment integrating to 6H suggests two equivalent methyl groups.
Final explanation

The evidence converges on Acetone; each clue supports the structure, but no single clue is treated as definitive.

Carboxylic acid comparison

C2H4O2

DBE 1; broad 2500-3300 cm−1 envelope; carbonyl near 1710 cm−1.

Progressive hints
  1. DBE points to one pi bond or ring.
  2. The broad O-H envelope plus carbonyl supports a carboxylic acid.
  3. The formula fits a two-carbon acid.
Final explanation

The evidence converges on Acetic acid; each clue supports the structure, but no single clue is treated as definitive.

Aromatic aldehyde

C7H6O

DBE 5; aromatic region; carbonyl; weak bands near 2720/2820 cm−1.

Progressive hints
  1. DBE 5 fits an aromatic ring plus a carbonyl.
  2. Aldehyde C-H evidence narrows the carbonyl type.
  3. A benzene ring plus CHO matches C7H6O.
Final explanation

The evidence converges on Benzaldehyde; each clue supports the structure, but no single clue is treated as definitive.

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