Question

define the term halochromism and discuss two different applications of halochromism. for each application , give 1 example of a typical halochromic compound used and briefly why each compound is halochromic include chemical structure. max 300 words

Answer 1

It changes the color of the substance. It is used as indicator. The phenomenon of halochromism is to add acids it stforms strongly colored salts to colorless or lightly colored salts.

Applications:

1. Photochromism: Light is induced, depends on isomerisation of two different molecular structures.

2. Halochromism:

It changes the color by P^H.

This includes phenophthalene and Titanium dioxide. This involved in acid-base reactions.

This is used in wound healing, urine, nasal discharge etc.

Photochromism is used in toys , logos on T-shirts etc.

Halochromism detects the acidity of substance. This occurs when the chemical binds to hydrogen and hydroxide ions in solutions. It results conjugated systems.