Page 134 - Chemistry_Form_2

Chemistry
for Secondary Schools

3. What will happen if magnesium ribbon is used instead of zinc granules.
Support your answer with a chemical equation.

Reactions of acids with metal oxides and metal hydroxide (neutralisation
method)
FOR ONLINE READING ONLY
The neutralisation method is usually used to prepare soluble salts such as sodium,
potassium, and ammonium salts. Metal oxides and metal hydroxides react with
acids to produce salt and water only.

Activity 5.8

Aim: To prepare potassium chloride
Requirements: Pipette, burette, conical flasks, dropper, evaporating dish,
tripod stand, wire gauze, heat source, 2 M potassium hydroxide
solution, 2 M hydrochloric acid solution, phenolphthalein indicator,
and distilled water
Procedure

1. Transfer 25 cm of 2 M potassium hydroxide solution into a conical flask.
3
2. Add two drops of phenolphthalein indicator.

3. Fill the burette with 2 M of hydrochloric acid. Record the initial reading.
4. Slowly run the acid from the burette into the conical flask while gently
swirling the flask to mix the acid and the base. Close the burette when the
solution just changes its colour. Record the volume of the acid used.
5. Transfer the mixture obtained into an evaporating dish and heat until all the
water evaporates.

Questions

1. What was the colour change of the reaction?
2. What volume of acid was used in the entire reaction?

3. What happened in Step 4? Explain with the aid of a chemical equation.

Student’s Book Form Two 127

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CHEMISTRY FORM TWO NEW 2025 DUMMY.indd 127