Chemical Indicators: Overview, Questions, Preparation

This chapter has multiple topics listed below:

Acids, Bases and Salts Acid Strength Difference between Acid and Bas...Examples of Bases Zinc carbonate Zinc Nitrate Aluminium Phosphate Aspartic Acid Butyric Acid Tannic acid Uses of Folic Acid Uses of Acetic Acid Lactic Acid formula Uses of Citric Acid Magnesium Nitrate Barium Iodide Dilute Acids Magnesium Phosphate Uses of Hydrochloric Acid List of Strong Acids Butanoic Acid Sodium Chlorate Barium Carbonate Chloroacetic Acid Magnesium Bicarbonate Red Cabbage Indicator Sodium Hexametaphosphate Zinc Hydroxide Potassium Iodate Peroxydisulfuric Acid Ph of Acids and Bases Potassium Bromate Weak Acid Examples Weak Bases Magnesium Hydroxide Monosodium Glutamate Potassium Hydroxide Nitrous Acid Henderson Hasselbalch Equation Difference between Alkali and B...Properties of Bases Sodium Citrate Ammonium Phosphate Chemical Indicators Chromic Acid Perchloric Acid Uses of Sodium Hydroxide Zinc Acetate

Yamini Saini

Updated on Jun 30, 2021 09:19 IST

Chemical indication, any material that provides a clear indication of the presence or absence of a threshold concentration of a chemical species, such as an acid or an alkali in a solution, usually by a difference of colour. The material called methyl yellow, which gives an alkaline solution a yellow hue, is an example. When acid is applied progressively, the solution stays yellow until much of the alkali has been neutralized, instantly turning the colour red. Methyl yellow is clear, like most markers, even though its concentration is as low as a few parts per million solution components.

Table of Contents

Natural Indicators
Illustrated Examples
FAQs on Colour Indicators

Natural Indicators

Turmeric

Turmeric, which we use for food processing in our everyday lives, can also be used as a chemical predictor. When applied with an acidic solution, the colour changes to yellow. But it changes its colour to brownish red when used as the base medium. This is the reason that when soap is added to it, a turmeric stain on a white shirt turns red.

China Rose

It is convenient to find China Rose (Gurhal). It changes its colour to green when a solution of Chinese rose is used with a simple solution, while it changes its colour to bright pink or magenta when used with an acidic solution.

Chemical Indicators in Class 10:

In class 10, you will get to learn about the basics, and more focus is there on the litmus paper indicator test. The weightage of this chapter is 4 marks.

Chemical Indicators in Class 11:

In Class 11, you will get to learn about the different indicators and how to perform their test

Chemical Indicators in Class 12:

In Class 12, there are some tests available to indicate some compounds.

Illustrated Examples

What is Litmus Indicator made of?

Litmus, a mixture of coloured organic compounds obtained from several species of lichens, especially Lecanora tartare and Roccella Tinctorum, which grow in the Netherlands.

How is litmus used?

One type of acid-base indicator is Litmus paper. The red paper is used to track alkaline pH and in the presence of a simple solution, it can turn a shade of blue. Blue litmus paper is used to screen for acids and when it comes into contact with an acidic solution, it can turn a shade of red.

What's the neutral colour of methyl orange?

Methyl orange has the property of yellowing with alkaline and neutral water. When the water gets acidic, it suddenly becomes red. At pH 4.3, the point of transition is.

FAQs on Colour Indicators

Q. What is the indicator of chemicals?

A. Chemical indication, any material that provides a clear indication of the presence or absence of a threshold concentration of a chemical species, such as an acid or an alkali in a solution, usually by a difference of colour.

Q. What is litmus used for?

A. In acidic solutions, Litmus turns red, and in alkaline solutions blue and is the oldest and most widely used measure of whether acid or a base is a product.

Q. How do indicators work?

A. The presence of H+ and OH- is detected by pH markers. By reacting with H+ and OH-, they do this: they are weak acids and bases. Deprotonation causes a colour difference if an indicator is a weak acid that is coloured and the conjugate basis has a different colour.

Q. What is in common with all the indicators?

A. Although most dyes do not change colour with the amount of acid or base present, several molecules respond to a change in the concentration of hydrogen ions, referred to as acid-base indicators. Poor acids themselves comprise most of the markers. On "litmus" paper, the most common predictor is found.

Q. What are the numerous pH predictor types?

A. PH markers, including phenolphthalein (range pH 8.2 to 10.0; colourless to pink), bromothymol blue (range pH 6.0 to 7.6; yellow to blue), and litmus, are some of the most commonly used pH measuring instruments (range pH 4.5 to 8.3; red to blue)