Acids and Bases

An Introduction to Acids and Bases

• Scientists tend to classify things and denoting them. For example, ‘acids and bases’.
• If a solution is neither an acid or a base, it is known as a neutral solution.

Properties of Acids and Bases

Acids	Bases
Taste sour	Taste bitter
Turn litmus paper red	Turn litmus paper blue
Are corrosive	Are corrosive
Release $H^{+}$ (hydrogen) ions	Release $O{H}^{-}$ (hydroxide) ions

Common Acids and Bases

• Some common examples of acids include…
  • Hydrochloric acid ($HCL$) - used in cleaning brickwork
  • Sulfuric acid ($H_{2}S{O}_4$) - used in car batteries
  • Acetic acid ($C{H}_{3}COOH$) - used in vinegar
• Some common examples of bases include…
  • Sodium hydroxide ($NaOH$) - used in soaps
  • Ammonium hydroxide ($N{H}_{4}OH$) - used in household cleaners
  • Sodium hydrogen carbonate ($NaHC{O}_3$) - used in baking soda

pH Scale

• pH scale stands for “potential of hydrogen”.
• ph scale is also logarithmic (10x, 100x, 1000x)

Indicators

• Indicators are substances that undergo colour changes in either acids, bases, or both.
• This allows scientists to identify a solution as acidic or basic.
• Some examples include litmus and universal.

Neutral Solution

• An example of a neutral solution would be water.

$H_{2}O\to O{H}^{-}+H^{+}$

• The charges of $H^{-}$ cancel with $H^{+}$, making it have a neutral charge. (See here for more information about charges, specifically ions.)

Neutralisation

• Neutralisation occurs with the following word equation.

Acid + Base → Salt + Water

• You can achieve a neutralisation reaction by applying this word equation in a chemical formula. For example…

Example of a Neutralisation Reaction

$HCL+NaOH\to NaCl+O{H}^{-}+H^{+}\to NaCl+H_{2}O$

• In the chemical formula, hydrogen and hydroxide combine to make water.
• Sodium and chloride form to make a salt.