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The part that water plays in acidity


This experiment explores the part played by water in the properties of acids.


This resource has been provided by, or developed in partnership with, Nuffield Foundation

Apparatus Chemicals

Eye protection

Each demonstration or working group requires:

Oven-dried beakers (100 cm3), 2

Teat pipettes (well dried), 2

6 V DC power pack (Note 1)

Connecting wires


6 V lamp

Steel electrodes, 2 (four pairs should serve up to a total of 16 working groups)

Paper tissues/towels

Universal indicator paper, dried, kept in dessicator or distributed in dry stoppered sample tubes (Note 2)


Oven-dried test-tubes (100 x 16 mm), 9 and stoppers to fit, 3

Oven-dried test tubes (150 x 25 mm), 3 and stoppers to fit, 3

Conical flask (100 cm3) to collect solution and stopper to fit

For making hydrogen chloride in methylbenzene:

Conical flask (500 cm3) 2

Beaker (500 cm3)

Dropping funnel (ideally a pressure equalising - Quickfit) (250cm3)

Filter funnel, (Quickfit) (1 dm3)

Drechsler bottle (or other glass container)

Rubber tubing

Stoppers or cork (for conical flask) 2

Marble chips (calcium carbonate), 2

Magnesium ribbon, cut into 1 cm lengths, 2

Dilute hydrochloric acid, 1 M, in a bottle labelled ‘Solution of hydrogen chloride in water’, 100cm3

Purified water

Methylbenzene (toluene) (HIGHLY FLAMMABLE, HARMFUL), 300cm3

Anhydrous calcium chloride 10-20 g

Concentrated sulfuric acid, CORROSIVE), 125cm3

Sodium chloride (or rock salt) 50 g

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


This experiment explores the part played by water in the properties of acids.


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.