# 7.13: Names and Formulas of Bases

Soap making has a long history. Until recently, soap was made using animal fats and lye from wood ashes. The lye served as a base to break down the fats and help form the soap. Needless to say, unless the soap was washed to remove the lye, it was very harsh on the skin. Many families would make their own soap by boiling the lye and fat in a large kettle over an open fire—a long and hot task.

## Bases

A base can be simply defined as an ionic compound that produces hydroxide ions when dissolved in water. One of the most commonly used bases is sodium hydroxide, illustrated below.

## Names and Formulas of Bases

There is no special system for naming bases. Since they all contain the $$\ce{OH^-}$$ anion, names of bases end in hydroxide. The cation is simply named first. Some examples of names and formulas for bases are shown in the table below.

 Table $$\PageIndex{1}$$ Formula Name $$\ce{NaOH}$$ sodium hydroxide $$\ce{Ca(OH)_2}$$ calcium hydroxide $$\ce{NH_4OH}$$ ammonium hydroxide

Notice that because bases are ionic compounds, the number of hydroxides in the formula does not affect the name. The compound must be neutral, so the charges of the ions are balanced just as for other ionic compounds. The sodium ion $$\left( \ce{Na^+} \right)$$ requires one $$\ce{OH^-}$$ ion to balance the charge, so the formula is $$\ce{NaOH}$$. Calcium $$\left( \ce{Ca^{2+}} \right)$$ requires two $$\ce{OH^-}$$ ions to balance the charge, so the formula is $$\ce{Ca(OH)_2}$$. Hydroxide ion is a polyatomic ion, and must be in parentheses when there is more than one in a formula.

## Summary

• Bases are ionic compounds that produce hydroxide ions when dissolved in water.
• The cation is named first followed by hydroxide.