WHAT ARE ACIDS AND BASES?

What is an acid?

—There are many definitions of what an acid is but here are two basic concepts. 

1. Arrhenius described an acid as a substance that releases hydrogen ions (H+) when dissolved in water (H2O).
—2. Bronsted-Lowry concept of an acid is any substance that produces a proton (H+) in solution. That is, a proton donor.

The strength of an acid

Strength of acid is measured by how easily it releases a hydrogen ion in solution

1. Strong acid, such as hydrochloric acid (HCl), separates (dissociates) completely in water and readily releases all of its hydrogen ions
2. Weak acid, such as acetic acid, does not completely separate in water; it releases only some of its hydrogen ions.

What is a base?

There are many definitions of what a base (alkaline) is but here are two basic concepts.

1. Arrhenius described a base as a substance that produces hydroxyl ions (OH-) when dissolved in water (H2O)
2. —Bronsted-Lowry concept of a base is any substance that accepts/binds freely to a proton ((H+) in solution. That is, a proton acceptor.

The strengtht of a base?

—1. Strong bases: They bind strongly to hydrogen ions. Examples: sodium hydroxide (NaOH) and ammonia (NH3)

2. Weak bases: They bind to hydrogen ions less readily Examples: aluminum hydroxide (AlOH3) and bicarbonate (HCO3-)