Chrominfo: December 2022

The major difference between natural and synthetic indicators is that natural indicators are those that come from or are made of substances that occur naturally, whereas synthetic indicators are compounds that are manufactured in a lab from artificial substances.

Compounds that change colour when added to acidic or alkaline solutions are called indicators. Indicators are often used to determine pH. Colored indicators can be added to the reaction mixture to determine the endpoint or equivalence point of different titration methods, such as acid-base.

Indicators are either weak acids or weak bases that change colour when the amount of hydrogen ions in a solution or its pH changes. In water, the indicators dissociate slightly to form ions. In chemistry, there are primarily two types of indicators: natural indicators and artificial indicators.

Natural indicators:

Natural indicators are naturally occurring substances that can be used to determine whether a substance is acidic or basic. These naturally occurring indicators are used to identify hydrogen ions (H+) and hydroxyl ions (OH-) in a sample solution.

Examples of natural indicators:

Turmeric, tomato, litmus, china-rose, clove oil, curry powder, red cabbage, vanilla extract, onion, grape juice, cherries, etc.

Natural indicator	Color in acid	Color in base
Turmeric	Yellow	Brick red
Beet root	Pink	Pale yellow
Red cabbage	Red	Green

Artificial indicators:

Indicators that do not occur naturally but are produced artificially in the laboratory or obtained through a chemical reaction are considered synthetic indicators. These synthetic indicators are used for titration, identifying acids and bases, and determining the pH of various solutions.