Only support for QID: 400291 - rationale & note correlate
@Brian_BH I noticed the changed tags do not include QID: 400291 & wanted to confirm which QID(s) is/are correct
Apologies; some of these are older tags before I had a full-throated appreciation of the preferred workflow for turning in tag suggestions.
403494 does indeed belong to a question that requires the understanding of shielding and NMR spectra, specifically how to predict the peak splitting of a proton as it would appear in an NMR graph. Requires the explicit knowledge of the n+1 splitting rule, and being able to discriminate this relative to a number of protons in various parts of a molecule, understanding which group would correspond to a specific peak splitting as exemplified.
Similarly, 403495 is a related question in which one is asked to predict the specific value for the downfield shift, in PPM, for an example proton in a given molecule. It requires understanding both the effects of shielding, whether this would cause upstream or downstream movement, and being able to discriminate between multiple options given for potential PPM value shifts.
401243 is a separate question, but involves identifying a peak on a given NMR graph and being able to discriminate between multiple protons in an example molecule and to predict where, on the given graph, a specific proton would appear. It requires understanding the effects of splitting caused by nearby protons, as well as judging the relatively height of the peak.
And lastly 401242 requires being able to judge, between two molecules, which would present with a given graph that would involve a peak integration greater than one. This requires the explicit understanding that peak integration is directly correlated to the number of protons present, and being able to identify that relative difference in proton abundance between two example molecules given.
Apologies for missing these rationales. I’ve got my workflow down now, and everything should be A+ going forward.
Thank you @Brian_BH for these rationales! We always appreciate thoroughness and you’ve explained each very clearly, so thank you! When it comes to tagging, we like to tag cards that directly relate to question content. 403495 seems to have a direct need for understanding how deshielding leads to a downfield shift. The others seem to have other notes that would be more fitting. For example, for the n+1 splitting rule with 403494, nid 1560293462556 (describes the purpose of the n+1 rule & what n represents) would be fitting
@Brian_BH Before moving forward with accepting QIDs 403495 & 400291, I wanted to ask for rationale for 401694 to determine if it’s directly connected to note content
401694 is a combination problem. It asks to predict which proton corresponds to a specific chemical shift. So it does directly require the knowledge that shielding affects chemical shift (in this case the given value is 4ppm, so it is being judged against more, and less, shielded protons also present in the molecule). The question also requires knowledge about splitting which is an additional discriminator, but the downfield position due to shielding is an important qualifier as there are four protons to choose from and both shielding and splitting are helpful in discriminating the correct answer choice.