Lewis and Bronsted acids and bases

[dana hu 1B]

Hello! I am still having trouble differentiating lewis and bronsted lowry acids and bases because they are so similar? If anyone has examples or a description to tell them apart, that would be great!
Thank you!

[Nina Tartibi 1F]

Hi!! Yes I was pretty confused on distinguishing the two of them until literally a couple hours ago when I went to the review session, but basically a Lewis acid is an electron pair acceptor, and a Lewis base is an electron pair donor. A Bronsted acid is a Hydrogen proton donor, and a Bronsted base is a Hydrogen proton acceptor. All Bronsted acids are Lewis acids, but not the other way around. You can recognize whether something is a Bronsted acid or base vs. Lewis acid or base because you would not be able to classify a compound as a Bronsted acid/base if it doesn't have Hydrogen involved.
Here's an example: Cl- + SO2 --> SO2Cl Cl has a negative charge, so it's more likely to donate a pair of electrons, therefore you know it's the base of the two reactants, and SO2 has a lone pair on the central atom, so it could also be the base, but it's more likely that Cl- is the base since it's unlikely that it would accept an electron pair. You can only classify these as a LEWIS acid and base, because there is no sign of Hydrogen protons in this reaction, therefore Bronsted is not applicable. Hope this helps!

[Connie Liang 3L]

Thanks Nina, that was super helpful!

[Tanner Bartyczak 1K]

I think I was in the same review session as Nina and I agree with her explanation.