What is the difference between an acid and a base?

Verified step by step guidance

1. An acid is a substance that donates protons (H⁺ ions) in a chemical reaction, while a base is a substance that accepts protons.
2. Acids typically have a sour taste and can turn blue litmus paper red, whereas bases have a bitter taste and can turn red litmus paper blue.
3. In aqueous solutions, acids increase the concentration of hydrogen ions (H⁺), while bases increase the concentration of hydroxide ions (OH⁻).
4. The strength of an acid or base is determined by its ability to dissociate in water: strong acids/bases dissociate completely, while weak acids/bases do not.
5. The pH scale is used to measure the acidity or basicity of a solution, with values below 7 indicating an acidic solution, values above 7 indicating a basic solution, and a value of 7 indicating a neutral solution.

Key Concepts

Acids

Acids are substances that can donate protons (H⁺ ions) in a chemical reaction. They typically have a sour taste and can turn blue litmus paper red. Common examples include hydrochloric acid (HCl) and sulfuric acid (H₂SO₄). Acids are characterized by their ability to increase the concentration of hydrogen ions in a solution.

Bases

Bases are substances that can accept protons or donate hydroxide ions (OH⁻) in a chemical reaction. They usually have a bitter taste and can turn red litmus paper blue. Examples include sodium hydroxide (NaOH) and ammonia (NH₃). Bases increase the concentration of hydroxide ions in a solution, which can neutralize acids.

pH Scale

The pH scale is a measure of the acidity or basicity of a solution, ranging from 0 to 14. A pH less than 7 indicates an acidic solution, while a pH greater than 7 indicates a basic solution. A pH of 7 is considered neutral, as seen in pure water. The scale is logarithmic, meaning each whole number change represents a tenfold change in acidity or basicity.