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SAI International School
CLASS VII
Subject- Chemistry
Topic: Acid Base & Salt
Sub-topic: Differences between acids and Bases, Indicators

CLASS ROOM ACTIVITY

EXPERIMENT:

To understand that that extract of China rose can be used as an acid base indicator.

Materials Required:

One beaker having 500ml capacity, four beakers having 200ml capacity, China rose
extract, four test-tubes containing vinegar, lime water, dilute HCl and NaOH solution.

Observation:

Students will be observed that extract of China rose changed

i) Colour of vinegar and dilute HCl from colourless to magenta
ii) Colour of lime water and NaOH solution from colourless to green.

Inference:

Extract of China rose can act as a natural acid base indicator which changes colour of acid
into magenta & colour of base into green.

1. Write the colour change takes place when China rose extract is added to the acid.

………………………………………………………………………………………….

…………………………………………………………………………………………

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