Brpnsted-Lowry acids, and

Distinguish Lewis acids and bases from Brpnsted-Lowry acids and bases. Give an example of each. 

Reactions (a) and (c) are reactions between Brpnsted-Lowry acids and bases the stronger acid and stronger base are identified. Reactions (b) and (d) occur between Lewis acids and bases. 

Examples of Brpnsted-Lowry acids and bases are given in Figure 2.1. 

If you took a good look at the information just presented, you might think that I made a couple of mistakes. Did you notice that I included water (HzO) and ammonia (NH3) as examples of both Brpnsted-Lowry acids and Brpnsted-Lowry bases This is no error. Water and ammonia are examples of amphoteric substances. An amphoteric substance is a substance that acts as an acid in some cases and as a base in other cases. Look at the following sets of reactions to see examples of these substances acting as both acids and bases. 

The Lewis concept deals with the behavior of electron pairs in chemical reactions. The same electron pairs we looked at when we discussed molecular geometry (see Chapter 6) can be involved in many reactions. Substances that can form a covalent bond by accepting an electron pair from another substance are known as Lewis acids. Substances that can form a covalent bond by donating an electron pair to another substance are known as Lewis bases. Be careful that you don t mix these up with the Brpnsted-Lowry acids and bases. It is easy to do since the words donate" and accept" are used, except they are associated with the opposite species (Brpnsted-Lowry acids donate protons, while Lewis acids accept electron pairs). 

Reagents that are classified as bases can be used with both Lewis and Brpnsted-Lowry acids and one application is the elimination of alkyl halides (E2 reactions sec. 2.9.A) in the presence of a base. Elimination involves conversion of a saturated moiety containing a leaving group to a molecule with a multiple bond. An example of this latter transform is ... 

How to determine protonation modes in reaction centers of enzymes is a very important issue in biochemistry [1-8], The protonation is obviously related to the catalytic activities of active side chains of amino residues the protonation and deprotonation to side chains of charged acids such as Glu, Asp, Arg, Lys, and His yield Brpnsted-Lowry acids and bases, catalyzing various chemical reactions. Also in metalloenzymes and these model systems, protonations are often critical parts of the reaction mechanisms. For instance, in (1) the water-oxidizing center (WOC) in photosystem II [9-14], (2) the Mn dimeric center in catalase [15-21], and (3) the Mn center in Mn superoxide dismutases (MnSODs)[22,23], the following reactions proceed, respectively ... 

Define and identify Brpnsted-Lowry acids and bases and identify conjugate acid-base pairs. (Section 16.2)... 

The fundamental difference between a Brpnsted-Lowry acid and a Lewis acid is that the former is a proton that accepts electrons and the latter is any other atom that accepts electrons. The fundamental difference between a Brpnsted-Lowry base and a Lewis base is that the former donates electrons to a proton and the latter donates electrons to another atom. 

A t5q)ical general chemistry course introduces Lewis acids (electron pair acceptors) and Lewis bases (electron pair donors) as well as Brpnsted-Lowry acids and bases. Note that defining acids as electron pair acceptors and bases as electron pair donors bypasses the need for ionization in water and simply focuses on transfer of electrons from one species to another. Apart from acids and bases, electron transfer is the fundamental requirement for a chemical reaction. A Lewis base must be electron rich in order to donate electrons. Likewise, a Lewis add must be electron deficient. In this book, Lewis bases will be confined to molecules that contain oxygen, nitrogen, a halogen atom, and sometimes sulfur or phosphorus. The structures of each Lewis base will be discussed in the context of each chapter. There are, however, some simple guidelines for identifying Lewis acids. ... 

Blood contains several substances that minimize changes in its acidity by reacting with either an acid or a base. One of these is the hydrogen phosphate ion, HP04. Write one equation showing this species acting as a Brpnsted—Lowry acid and another in which the species acts as a Brpnsted— Lowry base. 

The distinction between amphoteric and amphiprotic will be clearer after reading Chapter 18. Lewis theory is a more general acid-base theory that includes all Brpnsted-Lowry acids and bases. 

Given the formula of a Brpnsted-Lowry acid and the formula of a Br0nsted-Lowry base, write the net ionic equation for the reaction between them. 

COAL 9 Given the formulas of a potential Brpnsted-Lowry acid and a Brpnsted-Lowry base, write the equation for the possible proton-transfer reaction between them. 

Brpnsted-Lowry acids and bases An acid is a hydrogen ion donor a base is a hydrogen ion acceptor. 

Identify the reactant that is a Brpnsted-Lowry acid and the reactant that is a Brpnsted-Lowry base in each of the following ... 

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