5. Look at the picture and comment on it from the point of view of chemistry.

6. Ask different types of questions to the text “Titration” and answer your groupmates' questions.

7. Look through the text b. Make up the sentences of your own with the words in bold.

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8. Read the text. Which pH indicator is the most acidic? Which one is the most basic? Make up the graph showing the efficient pH range of these indicators. PH indicators

A pH indicator is an indicator used in the titration of an acid and a base which is also called a neutralization titration. A pH indicator indicates the neutralization point or end point or equivalence point by a change in color which is distinct.

pH Indicator List

The different indicators and their efficient range of pH are given below.

Indicator	pH range	Color acid solution	Color base solution
Cresol blue	1.2 - 1.8	Red	Yellow
Thymol blue	1.2 - 2.8	Red	Yellow
Methyl yellow	2.9 - 4.0	Red	Yellow
Methyl orange	3.1 - 4.4	Pink	Yellow
Methyl red	4.2 - 6.3	Red	Yellow
Litmus	5.0 - 8.0	Red	Blue
Bromothymol blue	6.0 - 7.6	Yellow	Blue
Phenol red	6.4 - 8.2	Yellow	Red
Thymol blue (base)	8.1 - 9.6	Yellow	Blue
Phenolphthalein	8.3 - 10.0	Colorless	Purple
Thymolphthalein	8.3 - 10.5	Colorless	Blue
Alizarin yellow	10.1 - 12.0	Blue	Yellow
Nitramine	10.0 - 13.0	Colorless	Orange/brown