■ Electrolysis
► | A decomposition process of an electrolyte by an electric current into its components. |
► | A type of cell which uses electrical energy to produce chemical reaction. | |
► | The animation below shows the basic structure of an electrolytic cell
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Laboratory Activity 6.2.1: Electrolysis of molten compounds |
■ Electrolysis of molten AxBy electrolyte
► | Metal compound is formed at the cathode. | ||||||||||
► | Non-metal is formed at the anode. | ||||||||||
► | In general, the electrolysis of molten electrolyte can be summarized as shown in the following table:
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► | Half-equation shows what happens at one of the electrodes during electrolysis. |
Predict the products of electrolysis of molten sodium chloride at anode and cathode.
Solution
Salt in molten state | At anode (+) | At cathode (-) |
Movements of ion to electrode | Cl- | Na+ |
Half equation | 2Cl- → Cl2 + 2e- | Na++ e- → Na |
Observation | Greenish-yellow gas | Grey metal is formed |
Product | Chlorine gas | Sodium metal |
✍ Worked-example 6.2(b)
Predict the products of electrolysis of molten magnesium oxide at anode and cathode.
Solution
Salt in molten state | At anode (+) | At cathode (-) |
Movements of ion to electrode | O2- | Mg2+ |
Half equation | 2O2- → O2 + 4e- | Mg2++ 2e- → Mg |
Observation | Colourless gas are released | Grey metal is formed |
Product | Oxygen gas | Magnesium metal |
⇲ For exercise(objective and subjective), download for free on Android OS. | ||
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