Match the Molecule to the Integration
The area under each ¹H NMR signal counts protons, so an integration ratio is a fingerprint of how a molecule's hydrogens partition into equivalent sets. Here we give you the ratio and three candidate structures: click the one consistent with it. Note that the candidates always show the same number of signals, so counting peaks is not enough — you have to work out each structure's proton partition.
Common Questions
Why can an integration ratio point to one structure out of several?
Integration reflects the symmetry of the molecule: how its hydrogens partition into equivalent sets. Candidates with the same number of signals can still partition their protons differently, and the ratio picks out the partition that fits. That is exactly how integration narrows down structures in real structure determination.
Can two different molecules give the same integration ratio?
Yes, easily: any two molecules whose hydrogens partition the same way share a ratio, which is why integration alone never proves a structure. In these problems the two wrong candidates are chosen to have genuinely different partitions, so exactly one structure fits.
Do I need the molecular formula here?
No. The ratio is relative, and the task is to compare partitions, not to count absolute protons. When you are ready for the harder version — three structures that all share the ratio, decided by shifts and splitting — that game is NMR Integration: Match the Spectrum.
Reconstructed from published data: assigned shifts from nmrshiftdb2 (CC BY-SA 4.0) · first-order rendering with typical J values.