Acids and Bases

Acids and bases are two large components of the chemical world. A human is made up of different amino acids. We use different bases when baking (baking soda). With this in mind, acids and bases are incredibly important in chemistry, biology and other applications in life. However, the fundamental question stands: what is the difference between an acid and a base?

Qualitatively, acids and bases have two very distinct odors, tastes and characteristics to them. These are as followed:

* Acids: Very sour tasting, corrosive to metals, less acidic when mixed with a base and they turn litmus paper red.

* Bases: Feels slippery, become less basic when mixed with an acid and they turn litmus paper blue.

However, while this is important to an extent, the most important bits of information for acids and bases is what they are like chemically speaking. Chemists spend their entire lives dealing with different types of acids. Biochemists worry about acids on a molecular level because amino acids are the building blocks of proteins. Therefore, acids are immensely important and need to be understood completely.

What is an Acid?

An acid is a compound that has a hydrogen ion. It can be a strong acid or a weak acid, but the rule for an acid is that it must contain a hydrogen ion. The hydrogen ion is a positively charged ion because it is the only charge a hydrogen can carry. More importantly, it was theorized that an acid can dissolve into water. When it does, the acid breaks into its two parts: it’s cation (positively charged) and its anion (negatively charged).

HCl -> H(+) + Cl (-) when mixed in water.

What the above demonstrates is that, when mixing an acid with water, the hydrogen ion and the chlorine ion split apart. The reason for this is because water acts like a base in this circumstance. However, when discussing bases, the water acts like an acid. That’s because water is amphiprotic. This means that it can carry acidic traits and basic traits depending on what it is being mixed with.

What is a Base?

A base is a compound that has a hydoxide ion. A hydroxide ion is an ion that is a combination of oxygen and hydrogen. A hydroxide ion is a negatively charged ion because the oxygen element has a -2 charge, but the hydrogen element has a +1 charge. Combine them together and the outcome is a -1 charge. Therefore, a hydroxide ion would look like OH-. When mixed with water, the base splits into its cation and anion.

NaOH -> Na(+) + OH (-) when mixed in water.

When mixing acids and bases together, the outcome is a new salt and water. For example, if mixing HCl (hydrochloric acid) and NaOH (sodium hydroxide), the outcome is water and the salt NaCl. It looks like this:

HCl + NaOH -> H2O + NaCl. The hydrogen ion that makes it an acid forms with the hydroxide ion that makes it a base and when combined, two hydrogen and an oxygen forms water. The sodium ion and the chlorine ion due to their opposite attraction (Na is positive, Cl is negative, opposite attract), they combine to form salt.