How to Compare & Contrast Acids & Bases

We all know acids and bases react chemically to each other and to other things, but what are they?

Acids and bases are known for their reactive nature, but few people know what they are on a chemical level, or how they compare and contrast to each other.

Water Ionization

Water molecules consist of two hydrogen atoms attached to an oxygen atom. The oxygen atom is very electronegative, meaning it hugs the electrons bonding the atoms together close to itself. Sometimes, it can pull the electrons entirely away from one of the hydrogen atoms, separating it. This looses two ions: one positive hydrogen ion (just a lone proton), and one negative oxygen-hydrogen pair, called a hydroxide ion. These ions are ever present in water in very small quantity, constantly separating and reforming elsewhere.

Acids vs. Bases

Acids are substances that like to either give up hydrogen ions, or bond with hydroxide ions. Either way, this tips the balance of the water ions in favor of more hydrogen ions. Bases are the opposite: They give up hydroxide ions or take in hydrogen ions, causing more hydroxide ions to be present in the water ions.

Strong vs. Weak

Different acids and bases give up their ions (or take in the water ions) either very easily or with more reluctance. For example, hydrochloric acid (HCl) consists of a very electronegative chlorine atom that quite easily lets go of the hydrogen nucleus attached to it, so it is a strong acid.

References

• Vision Learning: Acids and Bases
• Shodor: Acid-Base Chemistry