These compounds, such as Al 2 O 3 and Al OH 3 , are called amphoteric literally, "either or both" because they can act as either acids or bases. Al OH 3 , for example, acts as an acid when it reacts with a base. 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? Now let's look at lye, a strong base with the chemical formula NaOH sodium hydroxide. The sodiums don't do anything important, but the hydroxyls make the solution more basic. One last question: Why are strong acids and strong bases so nasty?
It's because they are out of balance. They either have too many positive charges and are looking for negatives to get back into balance, or they have too many negative charges and are looking for positives to get back into balance.
This makes them very reactive with anything they contact. When the positives and negatives are in equal number, they neutralize each other.
What is pH? The pH scale is a measure of acidity on a 14 point scale, where 7 is the neutral midpoint. You can buy electronic pH meters or pH indicator paper from any biological or lab supply company, which can be used to give you an accurate measurement of the acidic or basic quality of substances you want to test.
Try this simulation to determine the pH of some common substances. It can be regulated by the internal availability of substances chemicals , by adjusting breathing rate, and by eliminating chemicals in urine. Chemical buffers in the body are substances that can absorb extra hydrogen ions preventing a change in pH.
For example, during exercise muscle cells can produce excess lactic acid, which increases hydrogen ions acids release hydrogen ions. These hydrogen ions tend to make our body fluids more acidic, but chemical buffers in the body absorb them preventing a pH change. See below a table comparing what happens when acid or base are added to a plain solution no buffer , or to a solution that absorbs hydrogen ions or hydroxyl ions buffer.
Bicarbonate, phosphates, and proteins work as a chemical buffer in our body fluids. They absorb extra hydrogen ions or extra hydroxyl ions released from the things we make or eat. So your question holds only for strong acid like sulfuric acid you mentioned. As a user mentioned, not all acids dissociate that way. Sometimes, there is also the production of Hydronium ions. The hydronium ions react with the sulphate radical, forming an acid like entity.
Hence, the acidity is not lost. Yes, exactly; only ions can't not exist. Water molecule has dipole nature. So, now ions get hydrated as process of hydration takes place. They are still free entities, but surrounded by water dipoles. So, the solution of acid and water exists. Sign up to join this community.
The best answers are voted up and rise to the top.
0コメント