Acids and bases

Subject classification: this is a chemistry resource.

In chemistry, a compound could be an acid or a base. Acids and bases are very important in chemistry. They describe a large class of substances. Understanding their properties allows us to rationalize patterns that occur in chemistry.

Here is a list which contrasts their properties:

• Acids turn blue litmus paper red. Bases turn red litmus paper blue.
• Acids give off H+ (Hydrogen) ions in water; bases give off OH- (Hydroxide) ions in water.
• Acids generally taste sour due to the sour H+ ion; bases taste bitter due to the OH- ion; but they may have other tastes depending on the other part of the molecule.
• Bases are usually soapy in nature.
• Acids corrode active metals ; Bases denature protein.
• Acids have a pH less than 7 ; Bases have a pH greater than 7

Here is a list of properties that are common to both acids and bases

• When you dissolve an acid or base in water, it makes ions. This makes the water conduct electricity better.
• The stronger the acid (or base), the more ions are produced, so the conductivity of the solution increases.
• They can both conduct electricity.
• When an acid reacts with a base, a salt is formed
• They both can carry and share ions

Acids react with group 1 and 2 metals to generate hydrogen gas.

• Citrus fruits (Oranges, Lemons, Limes)
• Apples
• Pineapples
• Mangoes
• Water and soft drinks (Carbon dioxide reacts in water to form carbonic acid)
• Stomach acids
• Vinegar
• Liquid Drain cleaners containing sulfuric acid (Rooto)
• Any sour candy

Bases feel slippery and soapy and taste bitter because they hydrolyze the fatty acid ester of the skin (saponification reaction).

• Lye
• Baking soda
• Bleach
• Ammonia, e.g. window cleaner
• Wasp's sting
• Some Drain cleaner (Drano, Red Devil)
• Tooth paste