Acid-base reactions are interesting chemistry processes. In these reactions, an acid and a base come together. When they do, they create a salt and water. This type of reaction is called a neutralization reaction.

For example, when hydrochloric acid (HCl) mixes with sodium hydroxide (NaOH), they produce sodium chloride (NaCl) and water (H₂O).

Key Concepts

1. Definitions:

   • Acid: This is a substance that gives away protons (H⁺ ions) when mixed in a solution.
   • Base: A base is a substance that takes in protons or gives away hydroxide ions (OH⁻).

2. pH Scale:

   • The pH scale helps us understand how acidic or basic a solution is.
   • It ranges from 0 (very acidic) to 14 (very basic), with 7 being neutral, which means neither acidic nor basic.
   • For instance, lemon juice has a pH of about 2 (which is acidic), while soapy water has a pH of around 12 (which is basic).

3. Indicators:

   • Indicators are special substances that change color depending on the pH level.
   • For example, a universal indicator turns red in strong acids and purple in strong bases.

By knowing these basic ideas, you can better understand how different substances will react in an acid-base reaction. This knowledge is important for Year 12 chemistry!