u/SinisterRectus

Whilst tutoring a student, I wasn't able to give this a good explanation for this.

The question asked which is the most and which is the least significant resonance contributor among these three:

https://preview.redd.it/57br21pkxa2h1.png?width=782&format=png&auto=webp&s=8956794b772068daec245757057f3552c7caaf5e

My understanding is that C contributes the most because everything has a full octet. No issue there.

But the response indicated that A is the least contributing. Is there any good reason why B is better than A? I would have guessed that it is worse because oxygen is electron withdrawing through induction. Yes, oxygen is electron donating through resonance, but I don't think it is correct to use structure C to explain why B is better. Am I just forgetting my fundamentals? Does hyperconjugation contribute?

Hi. I couldn't find the answer to this on Xum's website, or on this subreddit. Does anyone here know why the metocin is provided as the benzoate salt? Thanks.

For example, a trip from Ruggles to BC includes a "transfer" from Back Bay to Copley, and shows the total fare as $2.40, but I'm pretty sure that if you leave Back Bay and enter Copley, you have to pay a new fare.

https://preview.redd.it/lfy11uetbszg1.png?width=422&format=png&auto=webp&s=b0c2f8eefab1c7d216ae23e3531820ef4bb9aeb4