Topic 1 Common acids and bases

Unit 10 acids and bases

Topic 1

common acids and bases

"Sour" must be familiar to you. The vinegar used for seasoning has a sour taste, because the vinegar contains acetic acid; some fruits have a sour taste, because the fruit contains various fruit acids. "Alkali" may not be as familiar to you as acid, but you have encountered it before.

Calcium hydroxide in lime water and sodium hydroxide in stove cleaner are both alkalis. Acids and bases are two different types of substances.

1. The role of acid, alkali and indicator

We have done experiments on the reaction of carbon dioxide and water. In this experiment, the carbonic acid produced by the reaction turned the purple litmus solution red. Litmus belongs to the acid-base indicator, and the acid-base indicator is usually referred to simply as the indicator. In addition to litmus, phenol is also commonly used as an indicator.

It can be seen that the acid can turn the purple litmus solution into red, but cannot change the color of the colorless phenol solution; the alkali can turn the purple litmus solution into blue, but the colorless phenol solution into red. Acids and bases can react with the indicator, causing the indicator to display different colors.

2. Common acids

1. Several common acid

Hydrochloric acid and sulfuric acid are both acids, and they have a wide range of uses.

Commonly used acids in laboratories and chemical production include nitric acid (HNO 3 ), acetic acid ( CH3COOH) , etc. In addition, many common substances in life also contain acid.

2. Corrosiveness of concentrated sulfuric acid

Concentrated sulfuric acid is highly corrosive. It absorbs moisture from paper, wood, cloth, and skin (all composed of compounds containing elements such as carbon, hydrogen, and oxygen) and produces black charcoal. So, be very careful when using concentrated sulfuric acid.

If water is injected into concentrated sulfuric acid, due to the low density of water, the water will float on the concentrated sulfuric acid, and the heat energy released during