 Hi, I'm Professor Nesheba and I'm here to tell you a little bit about Lewis acids and bases This is an introduction to the idea in which we're just going to use Lewis structures to Understand this this idea. So Lewis acid base chemistry requires a base And I'm just going to symbolize that as B. It's not any particular element I'm just writing B But the key thing is that this this Whatever the base is it has to have a lone pair of electrons So an example of that could be ammonia nitrogen with three hydrogens bonded to it, but it has a lone pair of electrons and So we think of the rest of this as B And there's the lone pair also water would be a good Lewis base because it has two lone pairs of electrons and The fluoride ion, you know because it has a full octet of Electron pairs would also be a good Lewis base. How about the Lewis acid? Well, the example that I'm giving you here is BF3 the main thing to note about the Lewis acid is What you look for is is an unfilled octet The point is that it has the capability of accepting This lone pair of electrons from the Lewis base and examples Well, I've given BF3 the silver ion so three-year-old good Lewis acids Now what's the stoichiometry of the reaction that happens? Well, the base with its lone pair combines with the acid to produce something called BA and the BA gets a special name in Lewis acid base chemistry and it's called the Lewis acid base adduct or just the adduct The thing to note about the adduct is that there is a bond between the B and A That bond also has a special name. It's called a dative bond and Finally the electrons that go into making that bond It's two electrons are the same as those electrons right there That is to say the Lewis base provided the electrons to make the dative bond