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Universal indicator ‘rainbow’

Description

A long glass tube is filled with a neutral solution of universal indicator. Hydrochloric acid is added to one end and sodium hydroxide solution to the other. The tube is inverted a few times to mix the solutions and the ‘rainbow’ of Universal indicator colours appears.

Type of Activity

:
demonstration

Audience

:
Teacher

Age Group

:
11 to 18 years

Credits

:
This is an experiment from the Practical Chemistry project, developed by the Nuffield Foundation and the Royal Society of Chemistry.
universal-indicator-rainb...



Apparatus Chemicals

Eye protection

For one demonstration, the teacher will need:

Glass tube (Note 1)

Bungs (rubber), 2, to fit the glass tube

Beaker (100 cm3)

Dropper pipettes, 3

Clamp stand, boss and clamp

Deionised or tap water

Hydrochloric acid, 0.1 M

Sodium hydroxide solution, 0.1 M (IRRITANT)

Universal indicator solution (HIGHLY FLAMMABLE)

Refer to Health & Safety and Technical notes section below for additional information.

 






A long glass tube is filled with a neutral solution of Universal indicator. Hydrochloric acid is added to one end and sodium hydroxide solution to the other. The tube is inverted a few times to mix the solutions and the ‘rainbow’ of Universal indicator colours appears.

ADDITIONAL INFORMATION

This is a resource from the Practical Chemistry project, developed by the Nuffield Foundation and the Royal Society of Chemistry. This collection of over 200 practical activities demonstrates a wide range of chemical concepts and processes. Each activity contains comprehensive information for teachers and technicians, including full technical notes and step-by-step procedures. Practical Chemistry activities accompany Practical Physics and Practical Biology.

The experiment is also part of the Royal Society of Chemistry's Continuing Professional Development course: Chemistry for non-specialists