in this video we're going to talk about lewis acids and lewis bases a lewis acid is basically an electron pair acceptor a lewis base is an electron pair donor so examples of electron pair acceptors are ions with positive charges such as h plus fe2 plus al3 plus these are all lewis acids they can accept a pair of electrons lewis bases are electron paired donors and any type of ion with a negative charge like chloride bromide these are lewis bases they have plenty of lone pair electrons to donate some other examples include hydroxide iodide water is the lewis base water can act as a lewis acid too but it can behave as both it can accept a pair of electrons or it can uh donate a pair of electrons what is amphoteric it can behave as an acid or as a base zinc chloride is another lewis acid bh3 all of these can accept a pair of electrons febr3 alcl3 these are some other lewis acids the methyl carbocation is a lewis acid a carb anion is a lewis base ammonia is another lewis base and so as you can see lewis bases they're basically nucleophiles they're electron rich and lewis acids are electrophiles they're electron poor now let's go over some reactions dealing with lewis acids and lewis bases so consider the reaction between boron trifluoride and ammonia ammonia is a lewis base it can donate a pair of electrons bf3 that's the lewis acid the boron atom can accept a pair of electrons so whenever you draw the curve arrows it's always going to go from the lewis base to the lewis acid and so the product of this reaction is going to look something like this a covalent bond is produced nitrogen is going to have a positive formal charge and boron is going to have a negative formal charge so that's the typical lewis acid lewis base reaction so let's work on some other examples what's going to happen if we put fecl3 and cl minus together you're going to get fecl4 minus but let's try it out so fecl3 like bf3 it has a trigonometry shape and this chloride has four lone pairs and a negative charge and so it's going to attach itself to the fe atom and now you're going to get this so now the iron atom has a negative formal charge now let's look at another example zinc chloride and h2o go ahead and predict the product of that reaction so let's draw it out so i'm going to draw zinc chloride like this and then we're going to react it with h2o oxygen has two lone pairs and so the oxygen atom is going to attack the zinc atom and we're going to have a trigonal planar shape around a zinc atom so now oxygen only has one lone pair but now it has a positive charge zinc is now going to have a negative formal charge and so that's going to be the product of that particular lewis acid-base reaction whenever oxygen has three bonds it typically bears a positive formal charge and whenever you add a new bond to a metal it usually carries a negative charge try this example this reaction will be reversible and you're going to get this albr4 minus so the bromide ion is going to attack the aluminum atom and so you're going to get albr4 it has a tetrahedral molecular geometry and the aluminum atom now carries the negative charge and so that's it and that's the basics behind a lewis acid-base reaction you