The Br nsted Definition of Acids and Bases. Even the Brnsted model is naive. The reaction between HCl and water provides the basis for understanding the definitions of a Brnsted acid and a Brnsted base.
Some chemists call it a hydrogen ion; others call it a proton. As a result, Brnsted acids are known as either hydrogen-ion donors or proton donors. Brnsted bases are hydrogen-ion acceptors or proton acceptors. Acids can be neutral molecules. The Brnsted theory therefore expands the number of potential acids. It also allows us to decide which compounds are acids from their chemical formulas.
Brnsted bases can be identified from their Lewis structures. According to the Brnsted model, a base is any ion or molecule that can accept a proton. To understand the implications of this definition, look at how the prototypical base, the OH - ion, accepts a proton.
The following compounds, for example, can all act as Brnsted bases because they all contain nonbonding pairs of electrons. The Brnsted model expands the list of potential bases to include any ion or molecule that contains one or more pairs of nonbonding valence electrons. The Brnsted definition of a base applies to so many ions and molecules that it is almost easier to count substances, such as the following, that can't be Brnsted bases because they don't have pairs of nonbonding valence electrons.
Which of the following compounds can be Brnsted acids? Which can be Brnsted bases? Click here to check your answer to Practice Problem 2. One interesting feature of water and many other covalent compounds is that they too can dissociate into ions. Unlike ionic compounds, such as sodium chloride, they are not ionized before they dissociate; they accomplish ionization and dissociation at the same time.
When water dissociates, one of the hydrogen nuclei leaves its electron behind with the oxygen atom to become a hydrogen ion, while the oxygen and other hydrogen atoms become a hydroxide ion. The hydroxide ion retains the electron left behind and thus has a full unit of negative charge, symbolized by OH-. In any sample of water, very few of the molecules are dissociated at any one time: in fact, only about one in million.
Create a free Team What is Teams? Learn more. Ask Question. Asked 6 years, 7 months ago. Active 3 years, 8 months ago. Viewed 4k times.
Improve this question. Resquiens Resquiens 5 5 silver badges 9 9 bronze badges. Add a comment. Active Oldest Votes.
A little Physical Chemistry: The following is how Pauling explained this. But the best description uses statistical thermodynamics … Which I will not get into. Improve this answer. Jan PhysicalChemist PhysicalChemist 2 2 silver badges 6 6 bronze badges. What is pH? What is a neutral solution? What is an acidic solution? What is a basic or alkaline solution? Chemical reactions in the body, the food we eat, medication we take, and the effects of some diseases can add or remove hydrogen or hydroxyl ions in or from our body fluids.
Then, all cells in our body depend on homeostatic regulation of acid-base balance to maintain pH within optimal living conditions.
There are several homeostatic mechanisms to maintain pH within optimal conditions.
0コメント