# What are acids and bases?

## Optional Activity: Household acids and bases

Look around your home and school and find examples of acids and bases. Remember that foods can also be acidic or basic.

Make a list of all the items you find. Why do you think they are acids or bases?

Some common acids and bases, and their chemical formulae, are shown in the table below.

 Acid Formula Base Formula Hydrochloric acid $$\text{HCl}$$ Sodium hydroxide $$\text{NaOH}$$ Sulfuric acid $$\text{H}_{2}\text{SO}_{4}$$ Potassium hydroxide $$\text{KOH}$$ Sulfurous acid $$\text{H}_{2}\text{SO}_{3}$$ Sodium carbonate $$\text{Na}_{2}\text{CO}_{3}$$ Acetic (ethanoic) acid $$\text{CH}_{3}\text{COOH}$$ Calcium hydroxide $$\text{Ca}(\text{OH})_{2}$$ Carbonic acid $$\text{H}_{2}\text{CO}_{3}$$ Magnesium hydroxide $$\text{Mg}(\text{OH})_{2}$$ Nitric acid $$\text{HNO}_{3}$$ Ammonia $$\text{NH}_{3}$$ Phosphoric acid $$\text{H}_{3}\text{PO}_{4}$$ Sodium bicarbonate $$\text{NaHCO}_{3}$$

Table: Some common acids and bases and their chemical formulae.

Most acids share certain characteristics, and most bases also share similar characteristics. It is important to be able to have a definition for acids and bases so that they can be correctly identified in reactions.