Page 24 - Chemistry - XI

Materials Required

Beakers (250 mL), test tubes, funnel and fi lter papers, pH paper or universal indicator, distilled water, dil.
HCl, dil. H SO , dil. NaOH, juice of diff erent vegetables/fruits, sodium acetate and acetic acid, ammonium
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4
chloride and ammonium hydroxide, NaCl and FeCl 3
Procedure

Determination of pH
1. Extract the juice from lemon, tomato, orange, pineapple, etc.
2. Take 2 mL of these juices in four marked test tubes 1, 2, 3, and 4, and add 2–3 drops of universal
indicator in each test tube and shake. Match the colour of the solutions with the standard pH chart
and determine the pH of the solutions.

3. Take some clean and dry test tubes and place various samples of fruit juices, and put a few drops of
each juice on diff erent strips of pH paper and compare the shade with those on the colour chart.
4. Take 100 mL of distilled water in six beakers A, B, C, D, E and F. In beaker A, add one drop of dil
NaOH and in beaker B, add one mL of dil. NaOH. In beaker C, add 1 drop of HCl and in beaker D, add
1 mL of HCl. In beaker E, 1 g of NaCl, and in beaker F, add 1 g of FeCl (ferric chloride).
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5. Shake the solutions well.
6. Take six test tubes marked 1, 2, 3, 4, 5, and 6.
7. Take 5 mL of solutions from each beaker in separate test tubes.
8. Add 2–3 drops of universal indicator in all the four test tubes.

9. Shake the test tubes and match the colour of the solution with a standard pH chart and note the
pH of these solutions and record it in observation table.
10. Add a few drops of sample from each test tube on the strips of pH paper and compare the shade and
colour with those on colour chart of universal indicator and record it in observation table.

Observation Table

pH of Acids, Bases and Salts

S. Sample pH paper Universal Indicator
No. Colour produced pH Colour produced pH

1. Very dil. NaOH

2. Dilute NaOH
3. Very dil. HCl

4. HCl (dil)

5. NaCl

6. FeCl
3

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