Page 131 - Chemistry_Form_2

Chemistry
for Secondary Schools

Uses of pH indicators
pH indicators are used in a variety of ways, including the following:

1. They are used to give rough pH values of chemical solutions and drinks such
as fruit juices and water.
FOR ONLINE READING ONLY
2. They are used in acid-base titrations to show the completion of a reaction
(end point).

3. They are used in agriculture to test the acidity or alkalinity of soil.
4. They are used to test the pH of water used in swimming pools to ensure that
the water used is approximately neutral.

5. They are used in wastewater monitoring to avoid environmental pollution.

Exercise 5.3

1. Explain the importance of using indicators in activities involving acids
and bases.

2 Explain one advantage and one limitation of using natural indicators.
3. How does the pH sensitivity of a synthetic indicator differ from that of a
natural indicator, such as hibiscus extract?

Salts

Task 5.5

Use online simulation and interactive tools or any other reliable resources to
investigate the properties, types, and everyday applications of salts.

A salt is an ionic compound which is made up of positively charged ions (cations)
and negatively charged ions (anions). Salts occur naturally and are also synthesised
in the laboratory. The main natural sources of salts include sea water and rocks.

Different salts are used in our homes and industries for various purposes. These
.
include table salt (NaCl), washing soda (Na 2 CO 3 10H 2 O), Plaster of Paris (POP)
.
(CaSO 4 H 2 O) and bleaching powder (Ca(OCl) 2 ).

124 Student’s Book Form Two

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CHEMISTRY FORM TWO NEW 2025 DUMMY.indd 124
CHEMISTRY FORM TWO NEW 2025 DUMMY.indd 124 01/08/2025 11:21:07