How are acids and bases distinguished?

Acids and bases are the two most widely used terms in our day-to-day life. We come across many things which are either acidic or basic in nature. These are the major classification of the substances in chemistry. Few compounds formed by the combination of acids and bases are known as salts. In this article, we will learn how substances can be distinguished as acids and bases.

Definition

The definition of acids and bases are given by various scientists based on their research and study. Scientists such as Robert Boyle, Arrhenius, and Lewis have different definitions for acids and bases. In general acids and bases can be defined as

Acid: An acid can be defined as a substance that comprises hydrogen which is proficient in donating a proton (hydrogen ion) to different substances. Acids have a sour taste in an aqueous medium. For example Sulphuric acid, Acetic acid, Citric acid, Hydrochloric acid, Tartaric acid and so on.

Base: A base can be defined as a molecule or ion able to accept a hydrogen ion from an acid. Bases have a bitter taste and are slippery to the touch. For example Sodium hydroxide, potassium hydroxide, Calcium hydroxide, Barium hydroxide etc.

Properties of acids and bases

Listed below are few properties of acids

• The nature of acids are mainly corrosive
• Acids are good conductors of electricity.
• When acids are treated with metals, they produce hydrogen gas.
• Acids usually taste sour

Listed below are few properties of bases

• Bases generally have a soapy texture and taste bitter
• Bases are good conductors of electricity in an aqueous medium
• Bases when dissolved in water produce hydroxide ions (OH– ions)

Litmus paper test

A type of filter paper that is used to test the given substance is acid or base is called Litmus paper.  It is a piece of paper that produces a result based on colour change. Litmus paper is filter paper that has been made with a lichen-derived natural water-soluble dye. If a substance is acidic then it turns blue litmus paper into the red. If a substance is basic then it turns red litmus into blue. If the substance is neutral if there is no color change on the paper. A litmus test is a quick test used in chemical labs to determine if a solution is acidic or basic.

The pH value test

The term Hydrogen potential is abbreviated as pH. The pH is defined as a measure of the concentration of hydrogen ions, in a solution to determine acidity or alkalinity. The pH scale varies from 0 to 14. At room temperature, if the aqueous solution has a pH of less than 7 then the solution is acidic and the solution is basic with a pH value higher than 7. The pH value of acid ranges from 1 to 7 and for bases it varies from 7 to 14. The optimum pH for our body and blood is about 7.2. The pH of pure water is 7 and it is suitable for drinking and cooking.

Applications

We come across a wide variety of solutions daily. Few solutions are acidic and few basic in nature. Listed below are few applications of acids and bases

• Lemons contain citric acid and is majorly used in cooking and in preserving foods
• In torch and batteries, sulphuric acid is the vital ingredient
• Nitric acid plays a prime role in fertilizers, paints, and dyes
• Sodium hydroxide is the key ingredient in the manufacture of soaps and detergents
• Magnesium hydroxide popularly known as milk of magnesia is used as an antacid in the treatment of acidity and gastric disorders
• Calcium hydroxide is used in painting and home decor items.

Acids and bases are the common day-to-day used substances. Each and every compound is determined and distinguished by its acidic and basic properties.