What do you Expect to See

If all the nuclei are non-equivalent, then all lines should have the same intensity (barring accidental overlap). If there are equivalent sets of nuclei, then the expected ratio is the product of the largest-to-smallest ratios of the various multiplets. Thus, for the above examples, three groups of two spin-1/2 nuclei gives a 1 2 1 triplet of 1 2 1 triplets of 1 2 1 triplets thus the maximum 

3 Are the Gross Features of the Spectrum Consistent with the Model  

The / -xylene anion radical is easiest. We expect to have four equivalent ring protons and six equivalent methyl protons. Thus we expect to see a 1 4 6 4 1 quintet of 1 6 15 20 15 6 1 septets. Spectrum (b) shows the quintet clearly, but the CH3 proton coupling is poorly resolved. No other isomer has a quintet, so we can assign (b) to the p-xylene radical anion. 

That leaves spectrum (c) for m-xylene. We expect two unique protons, one pair of equivalent ring protons, and six equivalent methyl protons. When we examine the wings of the spectrum, we see a 1 6 15 20 15 6 set of doublets. 

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In carrying out an analysis of a mixture, what do you expect to see when the TLC plate has been allowed to remain in the developing chamber too long, so that the solvent front has reached the top of the plate ... 

What would a MAS NMR of the p phase of white phosphorus (Figure 10.38) at very low temperatures look like What do you expect to see when the sample is measured at ambient temperature ... 

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