Difference between and Acid and a Base?

Question

What is the difference?

Answer 1

An acid contributes a surplus of hydrogen ions to a solution. A base contributes a surplus of hydroxide (OH) ions to a solution.

pH, the measurement of acidity/alkalinity, ranges from 0 (strongly acidic, many extra hydrogen ions) to 14 (strongly alkaline, many extra hydroxide ions).

When the ions are balanced (H + OH = Water, with none left over), the solution is neutral, and has a pH of 7.

Both acids and bases can react with other substances, and are often caustic. When they react with each other, a solution containing a certain kind of salt (depending on what kind of acid and base were used) is formed.

Answer 2

An acid contains a high concentration of Hydrogen+ Ions and a Base contains a lower concentration of Hydrogen+ Ions. On the pH scale an acid ranges from 1-6 and a base ranges from 8-16; 7 would be neutral. Examples:

Acid-Stomach Acid (Pepsin) or Hydrochloric Acid
Base-Sodium Hydroxide
Neutral-Pure Water

Answer 3

Acids have a sour taste and corrode most metals. They also produce a stinging sensation when touched. Examples include hydrochloric acid, fluorosulfuric acid, phosphoric acid, and nitric acid.

Bases have a bitter taste and a slimy, soapy feel. They react violently with acidic or reducible substances and are caustic to organic material. Examples include potassium hydroxide and sodium hydroxide. Ammonia is an example of a weak base.

On a pH scale, acids range from 0 to 6.5, while bases range from 7.5 to 14; water is neutral. Common substances in the acid range include soda, beer, coffee, and lemon juice. Substances in the base range include blood, hand soap, bleach and sea water.

Answer 4

An acid has a pH of LESS than 7 (It can go into negative numbers) and donates H+ ions when put in water to make the Hydronium Ion H30
EXAMPLE: HCl + H2O = H3O + Cl-

Bases have a pH of MORE than 7 (it can go over 14) and ACCEPTS H+ ions in water or donates OH- (Hydroxide Ion)
EXAMPLE: NH3 + H2O = NH4+ + OH-

Answer 5

You've asked a good question! Acids and bases have many similarities. They're both generally reactive to other molecules. Either one, if strong, can cause burns. Either can be weak or strong. Yet they're totally different types of molecules!

As another poster stated, acids are things that produce pH < 7. Bases are things with pH > 7. However, there are things which are acids and bases that won't mix with water, so a water-oriented definition is incomplete.

Consider the physical properties of acids and bases. Acids generally taste sour. If this seems odd, rember that citric acid is an important part of all citrus fruits.. which generally are sour.

Bases, on the other hand, often taste quite bitter. Many plants have bases in their makeup and are bitter to eat. For example, the bitter apple, or colocynth, has a high content of the base colchicine, and is used medicinally.

In general, contact with acid (particularly strong ones) will produce pain. It'll sting, and the stronger the acid the more it'll hurt. On the other hand, base burns are very tricky in part because they often absorb through the skin and THEN start eating away at the tissue, but also because the injured person often doesn't feel the burn until its severity is great.

There are three definitions chemists use to describe acids and bases. The oldest one, by a Dutchman named Arrhenius, is the easiest to grasp.

(1) Arrhenius described acids & bases in terms of what they did in water.

Arrhenius acid
something that reacts with water to produce hydronium ions, H3O+

Arrhenius Base
something that reacts with water to produce hydroxide ions, OH-

An example of an arrhenius acid is HCl (hydrochloric acid).

HCl + H2O --> H3O+ + Cl^-

An example of an arrhenius base is NaOH.

NaOH + H2O --> Na+ + OH- + H2O

This definition worked pretty well, but it wasn't perfect. For example, ammonia was known by its behavior to be a base (pH, sour taste, reactivity), but as there was no hydroxyl group (OH) on the molecule (NH3), it didn't qualify as a base under Arrhenius' definition. A lot of people thought about this problem, but it took over half a century for someone to come up with a good alternative explanation.

(2) Brønsted - Lowry Definition
Johannes Nicolaus Brønsted of Denmark and Thomas Martin Lowry (England) came up with an answer and published independently their answer (the same!) in 1923. They defined an acid and base in terms of movement of a proton (H+ ion).

Brønsted-Lowry Acid:
H+ donor (something that gives up protons).

hydrochloric acid is also a Brønsted acid, because the dissociation of HCl in water could be percieved instead in the following way:

HCl + H2O --> H+ + Cl- + H2O

Brønsted-Lowry Base:
Something that accepts a proton (H+).

NaOH is a Brønsted base, because the (OH) group could be said to be "accepting a proton".

NaOH + H2O --> Na+ + H2O + OH-

This one's harder to "see", but imagine that one hydrogen from the water molecule on the left migrates to the hydroxide from sodium hydroxide.

Na - OH + H - O - H --> Na+ + OH - H + OH-

Look familiar? All Arrhenius acids and bases are Brønsted-Lowry acids and bases. However, as I mentioned earlier, Brønsted-Lowry bases include things that aren't Arrhenius bases, such as ammonia.

NH3 + HCl --> NH4+ +Cl-
This is the formation of ammonium chloride by the reaction off ammonia and hydrochloric acid. Don't do it at home, its a little noxious and hot. Here, ammona (NH3) is the base because it accepts a proton (H+) from hydrochloric acid (HCl).

In 1923 an even MORE all-inclusive definition of acids & bases was also introduced. Gilbert N. Lewis, an American chemist, propsed that instead of looking at protons moving around, we should consider the movement of elctron pairs. Basically, his definition involves movement of electrons in the opposite direction that protons move (charge balance must be maintained!).

Then, in short, a Lews acid is something that ACCEPTS electron pairs.

A Lewis base is something that DONATES (gives up) electron pairs. If you've learned about electron-pushing yet (those arrows and dots), This is the most comprehensive definition of acids and bases, and accounts for why things like boric acid are acidic.

Answer 6

2

Answer 7

1

Answer 8

The PH level determines it. 0 -6 ACID 8- 15 BASE

7 being neutral like water

Answer 9

acid is proton donator n base is a proton acceptor..... then lewis explained it has acid id electron acceptor n base electron donor.. they also differ in ph below 7 acid above basic... when both r added it forms a salt

Answer 10

The PH level