This question is about electrolysis. Table 2.1 gives some information about the electrolysis of two electrolytes using graphite electrodes. Table 2.1 (i) Complete Table 2.1. (ii) Oxygen is produced at the anode by the electrolysis of aqueous copper(II) sulfate. Write the ionic half-equation for this reaction. ...................................................................................................................................

Chemistry

IGCSE&ALevel

CAIE

Exam No：0620_w24_qp_43. Year：2024 Question No：2(b)

Answer:

Knowledge points:

4.1.1. Define electrolysis as the decomposition of an ionic compound, when molten or in aqueous solution, by the passage of an electric current

4.1.10. Predict the identity of the products at each electrode for the electrolysis of a halide compound in dilute or concentrated aqueous solution

4.1.11. Construct ionic half-equations for reactions at the anode (to show oxidation) and at the cathode (to show reduction)

4.1.2.1. the anode as the positive electrode

4.1.2.2. the cathode as the negative electrode

4.1.2.3. the electrolyte as the molten or aqueous substance that undergoes electrolysis

4.1.3.1. molten lead(II) bromide

4.1.3.2. concentrated aqueous sodium chloride

4.1.3.3. dilute sulfuric acid using inert electrodes made of platinum or carbon / graphite

4.1.4. State that metals or hydrogen are formed at the cathode and that non-metals (other than hydrogen) are formed at the anode

4.1.5. Predict the identity of the products at each electrode for the electrolysis of a binary compound in the molten state

4.1.6. State that metal objects are electroplated to improve their appearance and resistance to corrosion

4.1.7. Describe how metals are electroplated

4.1.8.1. the movement of electrons in the external circuit

4.1.8.2. the loss or gain of electrons at the electrodes

4.1.8.3. the movement of ions in the electrolyte

4.1.9. Identify the products formed at the electrodes and describe the observations made during the electrolysis of aqueous copper(II) sulfate using inert carbon / graphite electrodes and when using copper electrodes

6.4.1. Use a Roman numeral to indicate the oxidation number of an element in a compound

6.4.10. Identify redox reactions by the colour changes involved when using acidified aqueous potassium manganate(VII) or aqueous potassium iodide

6.4.11. Define an oxidising agent as a substance that oxidises another substance and is itself reduced

6.4.12. Define a reducing agent as a substance that reduces another substance and is itself oxidised

6.4.13. Identify oxidising agents and reducing agents in redox reactions

6.4.2. Define redox reactions as involving simultaneous oxidation and reduction

6.4.3. Define oxidation as gain of oxygen and reduction as loss of oxygen

6.4.4. Identify redox reactions as reactions involving gain and loss of oxygen

6.4.5. Identify oxidation and reduction in redox reactions

6.4.6.1. loss of electrons

6.4.6.2. an increase in oxidation number

6.4.7.1. gain of electrons

6.4.7.2. a decrease in oxidation number

6.4.8. Identify redox reactions as reactions involving gain and loss of electrons

6.4.9.1. the oxidation number of elements in their uncombined state is zero

6.4.9.2. the oxidation number of a monatomic ion is the same as the charge on the ion

6.4.9.3. the sum of the oxidation numbers in a compound is zero

6.4.9.4. the sum of the oxidation numbers in an ion is equal to the charge on the ion

Answer:

Knowledge points:

Solution:

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