Jump to content

Rank the following molecules from most to least acidic?


gammagirl

Recommended Posts

Fellow companions,  I am following the rules of charge, atoms, resonance, inductive effects, and orbitals. For (c) I do not understand why molecule 1 is ranked first.  I would have thought molecule 3 would be the most acidic because of atoms and the ortho arrangement. Please enlighten me as soon as possible. Why would the first molecule win? Anyways, that is what the answer key says.

RenderedImage (1).jpg

Link to comment
Share on other sites

That's a tough one. Without any other information, I would have put them at about the same pKa. Indeed, looking it up, their pKa's are remarkably similar. If I were to guess, I would say that the 2-chloro substituent of compound 1 helps stabilise the conjugate base through inductive effects moreso than the phenyl ring does in compound 3. That is really what it comes down to with acidity. The more stable the conjugate base, the more favoured the dissociation is, meaning more H+ in solution and higher acidity. 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.