Page 108 - Chemistry_Form_2

Chemistry
for Secondary Schools

acid (HCOOH). The most
common acids that are found
in a chemistry laboratory
include hydrochloric acid,
FOR ONLINE READING ONLY
sulfuric acid, nitric acid,
and acetic acid. Common
acids in the laboratory
are stored in various
containers such as plastic
bottles or glass bottles as
shown in Figure 5.2.
Glass bottle Plastic bottle

Figure 5.2: Containers for storing acids in the laboratory

Properties of acids
Acids have certain physical and chemical properties.

Physical properties of acids
The following are the physical properties of acids:

1. Acids have a sour taste: A sour taste of vinegar, sour milk, and many unripe
fruits such as lemons, is caused by the acids present in them.

2. Most acids are water soluble: They can be diluted with water to reduce the
intensity of their acidity. Diluted acids feel watery unlike concentrated ones.
3. Acids have the ability to conduct electricity: When acids are dissolved in
water, they release ions which conduct electricity. The strength of acids as
electrolytes varies; strong acids ionise completely, while weak acids ionise
partially. This is why some acid solutions are commonly used in car and
solar batteries.

4. Acids have varied boiling and melting points, depending on their molecular
structures. Some acids have high boiling points, for example, sulfuric acid (337 °C),
whereas others have low boiling points, for example formic acid (100.8 °C).

5. Acids are corrosive in nature: Acids can have a corrosive action on various
substances such as paper as well as clothes. They can also damage or even
destroy metals. Therefore, they should be handled with extreme care;
otherwise they can corrode the skin.

Student’s Book Form Two 101

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