//Acid and Base: Introduction of Acid

Acid and Base: Introduction of Acid

We use various kinds of compounds in our chemical laboratories. Acids, bases and salts are most frequently used of them. As a chemistry learner, you also need to learn about acid, base and salt. In the laboratory, we mostly use diluted acid and base instead of concentrated acid or base. We take in acid, base and salt with our food which is essential for our body.


Acid is highly important among chemicals. It is a kind of chemical which, when dissolved in water decomposes into hydrogen ion or proton (H+).

Acids such as hydrochloric acid (HCI), sulfuric acid (H2SO4) etc. are concentrated acids, so they get easily decomposed in aqueous solution:

On the other hand, carbonic acid (H2CO3), acetic acid (CH3COOH) etc. are diluted acids. They get decomposed in aqueous solution in the following manner:

In the case of HCl and H2SO4, the decomposition is shown by a moonfaced arrow mark. It means that these acids get 100% decomposed in water. That is why they are called concentrate acids or strong acids.

The decomposition of the latter two acids is shown with dual faced arrows that mean they are partially decomposed in water. That is why they are called dilute acids or weak acids.

Let’s analysis an example, at 25°C temperature, out of 1000 CH3COOH molecules, only 4 will be decomposed in water. The rest 996 molecules remain intact in water.

When the amount of acid in the solution of acid and water is higher than water, then the solution is called concentrate acid. And when the amount of water in such solution is higher, then it is known as dilute acid.

Acids are tasted sour. You have certainly tasted tamarind which is too sour. Since it contains tartaric acid which makes it sour. Blue litmus turns into a red colour when it is put in an acidic solution.

However, acid undergoes reaction with metallic oxide and produces salt and water.

Acid undergoes reaction with more reactive metals and produces salt and hydrogen gas.

The food items that we take every day contain various acids. For example, milk contains lactic acid, soft drinks contain carbonic acid, tamarind has tartaric acid, lemon or orange has citric acid, Vinegar has ethanoic acid, tea contains tannic acid etc.

When we eat or take these foods, the acids go inside our body. They help us to digest our food and prevent diseases. Besides these, there are pickles containing different acids which act as appetizers. Since these acids are dilute/ weak they cannot harm our health. Inside the body, the stomach wall generates hydrochloric acid (HCl) which is very strong acid. It is used for decomposing food inside.

However, sometimes excess secretion of HCl occurs from the stomach which starts to decompose the cells of the stomach wall. Again, if we remain hungry or keep our stomach empty, the HCl decomposes the cells of stomach and corrosion is thus created there for which we feel pain in the stomach. This situation is called peptic ulcer.

Therefore, we need to avoid the foods that cause excess secretion of acid and do not stay without food for a long time as well.