Acids

There are acids in the laboratory, for example hydrochloric acid, sulphuric acid and nitric acid. But there are also natural acids in vinegar, sour fruits like lemon and even your stomach! When an acid is dissolved in lots of water, it is called dilute. The more concentrated an acid, the less water it is dissolved in.

Concentrated acids are corrosive. This means they burn through skin, other living tissue and metal.

Bases and Alkalis

Bases are the chemical opposite of acids. They react strongly with acids in neutralization reactions. In such a neutralization reaction, bases neutralize acids which means that they cancel out the acid effect. If a base is soluble in water it is called an alkali.

Alkalis in concentrated solutions are corrosive like acids. This powerful chemical action is often used in bath and oven cleaners.

Neutralization

Although neutralization may seem like something that only happens in the lab, it is also used at home. Stomach indigestion is usually caused by too much acid in the stomach. The pain from indigestion can be removed if the acid is neutralized. This can be done by swallowing a weak alkali like bicarbonate of soda or milk of magnesia.

Neutralization also occurs when treating wasp or bee stings. A wasp sting is an alkali and can be treated with vinegar which is a weak acid. The vinegar neutralizes the alkali wasp venom. A bee sting is an acid and can be neutralized using baking soda which is a weak alkali.

Farmers use neutralization when too much acid is in the soil is causing it to be “sour”. They normally add lime to their fields. Lime is an alkali that dissolve in rain water and neutralizes the acid in the soil. Crops can now grow better.

Questions

1. Name three laboratory acids.
2. Name three acids you have in the home.
3. What is meant by dilute?
4. What is meant by concentrated?
5. What is meant by corrosive?
6. What are bases? What are alkalis?
7. What happens in a neutralization reaction?
8. Where are alkalis used in the home?
9. How can you treat stomach indigestions? Why does it work?
10. How can you treat bee and wasp stings? Why does it work?
11. Why do farmers sometimes add lime to their fields?

Challenge: Why is it important to use a weak alkali when treating stomach indigestion and bee stings?

Why do you have to use a weak acid to treat wasp stings?