Identifying Bases
Sodium hydroxide, NaOH, is an example of a base. A base is a compound that produces hydroxide ions (OH−) when dissolved in water. When sodium hydroxide dissolves in water, it dissociates into sodium ions and hydroxide ions.
Figure 17 lists some common bases and their uses. Like acids, bases have certain physical and chemical properties that you can use to identify them. 
Some general properties of bases include bitter taste, slippery feel, and ability to produce color changes in indicators. Unlike acids, bases usually do not react with metals. However, low reactivity with metals is not considered a general property of bases. For example, sodium hydroxide reacts very vigorously with metals such as aluminum and zinc.
Bitter Taste
Have you ever tasted unsweetened chocolate (sometimes called baking chocolate)? Without sugar, chocolate tastes bitter. Cacao beans contain a base called theobromine that gives unsweetened chocolate its bitter taste.
Many cough syrups and other liquid medicines contain similar bases. Fruit flavorings are often added to mask the taste of these basic solutions.
Slippery Feel
Bases feel slippery. Wet soap and many cleaning products that contain bases are slippery to the touch. When wet, some rocks feel slippery because the water dissolves compounds trapped in the rocks, producing a basic solution.
| Common Bases | ||
|---|---|---|
| Name | Formula | Uses |
| Aluminum hydroxide | Al(OH)3 | Deodorant, antacid |
| Calcium hydroxide | Ca(OH)2 | Concrete, plaster |
| Magnesium hydroxide | Mg(OH)2 | Antacid, laxative |
| Sodium hydroxide | NaOH | Drain cleaner, soap production |
Figure 17 A base is a compound that produces hydroxide ions when dissolved in water. The plaster in this boy's cast contains a base. Bases are also commonly found in products used for cleaning.
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