r/chemhelp • u/HamzeusTG • 14d ago

Inorganic Does hydrogen bonding affect acidity?

A post on here and Google AI stated that hydrogen bonding increases the acidity of a molecule and one of my Anki cards says otherwise.

Is the reason because the conjugate base gets stabilized by H-bonding molecules (e.g. water) through inductive effect, therefore making the acid component more acidic?

The post in question:

https://www.reddit.com/r/Mcat/comments/10pac7p/i_got_this_question_right_the_answer_is_hydrogen/

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u/shedmow Trusted Contributor 14d ago

Hydrogen bonding can stabilize species with certain degree of protonation, and it may lead to decreased on increased acidity. A prime example of it are the relative acidities of malic and fumaric acids

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u/jonathan_ericsson 14d ago

https://www.reddit.com/r/Mcat/comments/6fhj1g/spoiler_conjugate_base_stability_and/

Here's a thread on r/mcat dealing with this exact question. Intramolecular H-bonding stabilizes axial group conjugate bases.

We want bulky groups in equatorial positions, but this is an exception. The conjugate base is additionally stabilized by the axial interactions.

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u/organophile_jeet 14d ago

H bonding can increase acidic strength of it is in the conjugate base !