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How can hardness in water be removed?

Description

The hardness of temporarily and permanently hard water is tested using soap solution.

Credits

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

The teacher will require:

Eye protection

Beakers (500 cm3), 3

Bunsen burner

Tripod and gauze

Heat resistant mat

Vacuum filtration apparatus (Note 1)

Ion exchange apparatus (Note 2)

Gas generator for carbon dioxide (Note 3), or a CO2 cylinder

Each student or group of students will need:

Test-tubes, 9

Test-tube rack

Labels, for test tubes

Beaker (100 cm3)

Dropping pipette

Spatula

The teacher will require:

Calcium sulfate solution, 300 cm3(Note 4)

Limewater (IRRITANT), 150 cm3

Sodium zeolite, about 5 g (Note 2)

Marble chips

Dilute hydrochloric acid, 2 M (IRRITANT)

Each student or group of students will need:

Solutions labelled as shown below, 100 cm3 each

A Temporarily hard water*

B Permanently hard water (Note 4)

C Temporarily hard water that has been boiled and filtered*

D Temporarily hard water that has passed through an ion exchange column*

E Permanently hard water that has passed through an ion exchange column*

F Distilled water (or deionised water)

* These are prepared by the teacher in the demonstration part of the experiment

Soap solution in IDA (Industrially Denatured Alcohol) (HIGHLY FLAMMABLE, HARMFUL), 10 cm3 (Note 5)

Sodium carbonate-10-water (IRRITANT), about 1 g

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

 

 








The hardness of temporarily and permanently hard water is tested using soap solution.

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.