1. Chemistry in Action Acids and bases
Unit 1 Science 20F
Chemistry in Action Acids and bases

2. Acids and Bases
There are special compounds that have very specific properties
Acid is a covalent compound that has an H+ ion upon dissociation
In other words, most acids start with a hydrogen
ex: HCl, HNO3, H2SO4
One major exception is acetic acid, CH3COOH

3. Base is an ionic compound that gives off an OH- ion upon dissociation
In other words, bases all end in OH
ex: NaOH, KOH, Al(OH)3
One major exception to this rule is ammonia, NH3
Salt is an ionic compound that doesn’t give H+ or OH- ions upon dissociation
ex: NaCl, MgBr2, KNO3

4. Properties of Acids and Bases
a) they ionize in water
b) acids react with metal to make H2 gas
c) acids turn blue litmus red
d) acids neutralize bases
e) acids have a sour taste

5. Properties of Bases:
a) bases are electrolytes
b) bases turns red litmus blue
c) bases neutralize acids
d) bases taste bitter and feel slippery
e) bases dissociate because they are ionic
Acids and bases can be rated for strength based on a special scale called the pH scale

6. Developed in 1909 by Soren Sorenson
It refers to the power of the H+ concentration in a solution
The actual scale looks like:
neutral
increasing acidity
increasing basicity
vinegar 1 2 3 11 14
6.5 7
Digestive juices/ Coke
Milk of Magnesia
Milk

7. To test if a substance is an acid or a base we can use chemicals called “indicators”.
The most common indicator is litmus paper. It turns red if in an acid and blue if it’s in a base.
Sometimes we’d like to have a more specific idea of the pH so we use liquid indicators.
Some examples of liquid indicators include phenolphthalein, bromothymol blue, universal indicator, etc…

8. Naming Acids and Bases
There are two possibilities when trying to name acids:
1) Hydrogen plus one other element
Name these as “hydro ______ic acid”
ex: HCl is hydrochloric acid
H2S is hydrosulfuric acid
2) Hydrogen plus a complex ion
Name these as “_______ic acid”
ex: H2SO4 is called sulfuric acid
H3PO4 is called phosphoric acid

9. Bases are simple to name
Bases are simple to name. Just write the first element’s name followed by “hydroxide”
ex: NaOH is sodium hydroxide
Al(OH)3 is aluminum hydroxide

10. Neutralization Reactions
When a strong acid and a strong base mix together they neutralize each other
They will always make water and a salt (some ionic compound)
It will be your job to figure out what that salt is.
Write water as HOH
Don’t forget to criss-cross the salt because it is an ionic compound!

11. ex: HCl + NaOH →
HOH
NaCl
HCl + NaOH → HOH + NaCl
ex 2: H2SO4 + KOH →
K2SO4
HOH
H2SO4 + KOH → HOH + K2SO4 2 2