Acid

• In chemistry, the term acid can refer to several different properties of a substance, including a sour taste and the production of hydrogen ions when dissolved in water.
  
  

Base

• A base is chemically the flip side of an acid and is a substance that produces the so-called hydroxyl ion (OH) when dissolved in water.
  
  

pH

• The degree of acidity of a substance is measured on the pH scale which runs from 0 to 14. Zero is a strong acid, 14 is a strong base and 7 is neutral.
  
  

Buffer

• A buffer is a solution containing chemical compounds that moderate acidity, tending to keep the pH steady even as more acids or bases are added.
  
  

Examples

• There are some familiar examples of acids such as vinegar, which is acetic acid, and bases such as lye, which is sodium hydroxide.