Definitions and Theories
What is an acid, base, or alkali?
These things are not defined by their properties, so before you can define them you first have to know the three theories below.
These things are not defined by their properties, so before you can define them you first have to know the three theories below.
![Picture](/uploads/2/7/9/1/27911355/104448140.jpg)
Arrhenius Theory
Svante Arrhenius developed his theory of acids and bases in 1887 and won a Nobel Prize for his efforts.
His theory comes down to this:
Svante Arrhenius developed his theory of acids and bases in 1887 and won a Nobel Prize for his efforts.
His theory comes down to this:
- An acid is a substance that dissociates in water to form H+ ions
- A base is a a substance that dissociates in water to form OH- ion
Brønsted–Lowry Theory
This theory was discovered in 1923 by Johannes Nicolaus Bronsted and Thomas Martin Lowry and was seen as an improvement over the Arrhenius theory. Their theory said that:
This theory was discovered in 1923 by Johannes Nicolaus Bronsted and Thomas Martin Lowry and was seen as an improvement over the Arrhenius theory. Their theory said that:
- An acid is an H+ donor
- A base is an H+ receiver
![Picture](/uploads/2/7/9/1/27911355/641244032.jpg)
Lewis Theory
Gibert N. Lewis also developed his theory in 1923 but he defined acids in bases in terms of electrons. His theory comes down to:
Gibert N. Lewis also developed his theory in 1923 but he defined acids in bases in terms of electrons. His theory comes down to:
- An acid is an electron pair acceptor
- A base is an electron pair donor
Now that you know the theories you can define acids and bases as:
What about Alkalies?
Alkalies are just bases that dissolve in water giving the water a pH above 7. Thus they have everything a base does .
- An acid is a substance that forms H+ ions in water,is an H+ donor, and an electron pair acceptor
- A base is a substance that forms OH- ions in water, is an H+ recover, and an electron pair donor
What about Alkalies?
Alkalies are just bases that dissolve in water giving the water a pH above 7. Thus they have everything a base does .
Conjugate Acid/Base
What are conjugate acids/bases?
The short answer is that a conjugate acid is the product that received the H+ and the conjugate base is the product that donated the H+.
Confused? The full explanation is below. If not? Congrats! you can go right to the quiz here
The conjugate acid and base are the products of a neutralization reaction. Let's go back to the Bronsted- Lowry theory for a moment to explain that. By their definitions an acid is an H+ donor and a base is its receiver. When you combine an acid and a base in a neutralization reaction you get a conjugate acid and base.
TADA!
Acid + Base = Conjugate Acid + Conjugate Base
During the reaction the acid donates its H+ ions to the base and the base takes it. The conjugate acid is the product that got the H+ (it used to be the base). The conjugate base is what no longer has the H+ (it used to be the acid).
Before you go let's do one example together. Below there is a chemical equation, let's identify all its parts.
HF + H2O→F− + H3O+
First let's identify the acid by finding the lone H+ ion. Once you've found that, the other reactant must be the base. Now look at the products. See which reactant gained a hydrogen ion on the product side. That's the conjugate acid so the other product must be the conjugate base. You can also look to see which product no longer has the H+ ion to find the conjugate base. If you feel ready you can test yourself on this by clicking here.
The short answer is that a conjugate acid is the product that received the H+ and the conjugate base is the product that donated the H+.
Confused? The full explanation is below. If not? Congrats! you can go right to the quiz here
The conjugate acid and base are the products of a neutralization reaction. Let's go back to the Bronsted- Lowry theory for a moment to explain that. By their definitions an acid is an H+ donor and a base is its receiver. When you combine an acid and a base in a neutralization reaction you get a conjugate acid and base.
TADA!
Acid + Base = Conjugate Acid + Conjugate Base
During the reaction the acid donates its H+ ions to the base and the base takes it. The conjugate acid is the product that got the H+ (it used to be the base). The conjugate base is what no longer has the H+ (it used to be the acid).
Before you go let's do one example together. Below there is a chemical equation, let's identify all its parts.
HF + H2O→F− + H3O+
First let's identify the acid by finding the lone H+ ion. Once you've found that, the other reactant must be the base. Now look at the products. See which reactant gained a hydrogen ion on the product side. That's the conjugate acid so the other product must be the conjugate base. You can also look to see which product no longer has the H+ ion to find the conjugate base. If you feel ready you can test yourself on this by clicking here.
Properties
Below are some of the properties of acids and bases. Although you can't define an acid or a base by its properties, they can help you figure out if something is an acid or a base.
Acids
|
Bases
|
Uses in Life
Acids and bases find their way into to your life all over the place, from the food you eat to what cleans your clothes. Take a look at the pictures for some examples!