Lewis and Bronsted

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Montana James 4G
Posts: 46
Joined: Wed Sep 18, 2019 12:21 am

Lewis and Bronsted

Postby Montana James 4G » Wed Nov 27, 2019 9:51 pm

kind of a stupid question, but I'm just confirming that a Lewis base is the same thing as a Bronsted base, just with different ways of explaining it? in other words, am I correct in saying that it's not possible for a substance to be both a lewis acid and a bronsted base?

Ally Huang- 1F
Posts: 103
Joined: Thu Jul 25, 2019 12:16 am

Re: Lewis and Bronsted

Postby Ally Huang- 1F » Wed Nov 27, 2019 10:01 pm

I believe they are pretty much the same thing. Lewis base is a more general term for a Bronsted base. Bronsted base must donate a pair of electrons to an acidic hydrogen and a lewis base is anything that donates a pair of electrons anywhere to another molecule. For your second question, it is possible for something to be a lewis acid and a bronsted base as water is an example.

karinaseth_1A
Posts: 57
Joined: Sat Jul 20, 2019 12:15 am

Re: Lewis and Bronsted

Postby karinaseth_1A » Wed Nov 27, 2019 10:10 pm

Yes, a Lewis acid and Bronsted acid describe an acid, just in different ways and in terms of different types of behavior. The Bronsted definition of an acid is proton (H+) donor, while the Lewis definition of an acid is an electron-pair acceptor. Essentially, acids are electron deficit species that dissociate (give up their H+ ion) and take on electrons from the base or solvent.

Caitlyn Tran 2E
Posts: 100
Joined: Fri Aug 09, 2019 12:15 am

Re: Lewis and Bronsted

Postby Caitlyn Tran 2E » Thu Nov 28, 2019 12:52 am

Yes, the main difference between Bronsted acids and bases compared to Lewis acids and bases is merely what they focus on in their definitions. The Lewis acid and base definition is more general since a Lewis acid is simply an electron pair acceptor while a Lewis base is an electron pair donor. The Bronsted acid and base definition is more specific since a Bronsted acid donates a proton (H+ ion) while a Bronsted base accepts a proton (H+ ion). Since Bronsted acid and base definitions only involve H+ ions while Lewis acids and bases involve electrons in general, a Bronsted acid is always a Lewis acid and a Bronsted base is always a Lewis base, but the reverse is not necessarily true. Hope this helps!

Brynne Burrows 3K
Posts: 52
Joined: Thu Jul 25, 2019 12:16 am

Re: Lewis and Bronsted

Postby Brynne Burrows 3K » Thu Nov 28, 2019 12:04 pm

A Lewis base means that molecule is donating its lone pair, while the Bronsted base accepts a proton. The molecule is still a base either way, it is just the way of wording that changes if its called Lewis or Bronsted.


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