Assessment Test Electrolysis Practice Test PDF Certifications Certifications Electrolysis Practice Test PDF Questions Available Here at: https://www.easy-quizzz.com/gb/certification-exam/assessment-test/electrolysis-past- paper-questions/quiz.html Enrolling now you will get access to 502 questions in a unique set ofElectrolysis Practice Test Question 1 A copper(II) sulfate solution is electrolysed using copper electrodes. Compared with using platinum electrodes, what change is expected at the anode? Options: A. Copper ions are reduced and the anode gains mass B. Water is oxidised and the anode remains unchanged C. Copper atoms are oxidised and the anode gradually dissolves D. Sulfate ions are reduced and the anode becomes coated with copper Answer: C Explanation: Copper is an active electrode in copper(II) sulfate solution, so copper atoms at the anode are oxidised to Cu² ions and enter the solution, causing the anode to lose mass. Platinum is inert and would not normally participate in this electrode reaction. Question 2 In a membrane cell used for the industrial electrolysis of concentrated brine, the membrane separates the anode and cathode compartments. What is the main reason for this separation? Options: A. To prevent chlorine from reacting with sodium hydroxide formed at the cathode B. To increase the electrical conductivity of the brine solution C. To ensure that hydrogen is oxidised at the anode instead of chloride ions Certifications Certifications Electrolysis Practice Test PDF https://www.easy-quizzz.com/gb/ D. To allow sodium ions to be discharged preferentially at the cathode Answer: A Explanation: Chlorine is produced at the anode, while hydrogen and sodium hydroxide are formed in the cathode compartment. The membrane allows sodium ions to pass through but limits mixing, preventing chlorine from reacting with sodium hydroxide to form unwanted products such as hypochlorite. Its main purpose is not to increase conductivity or change which species is discharged. Question 3 In the electrolytic extraction of aluminium, alumina is dissolved in molten cryolite rather than electrolysed as pure molten alumina. What is the main purpose of using cryolite? Options: A. To react with aluminium oxide and form aluminium chloride B. To lower the operating temperature and improve the electrolyte's electrical conductivity C. To prevent oxygen ions from reaching the positive electrode D. To provide the aluminium ions that are discharged at the negative electrode Answer: B Explanation: Cryolite dissolves alumina, lowers the melting point of the mixture and improves its electrical conductivity, making electrolysis more practical. It does not supply the aluminium ions; those come from the dissolved aluminium oxide. Question 4 A steel component is to be coated with copper using an aqueous copper sulfate solution and a copper electrode. Which arrangement will produce the intended coating? Options: A. Connect the steel component to the positive terminal and use the copper electrode as the cathode B. Connect both electrodes to the negative terminal so copper ions are attracted to the steel C. Connect the steel component to the negative terminal and use the copper electrode as the anode D. Connect the steel component to the positive terminal and use an inert electrode as the anode Answer: C Certifications Certifications Electrolysis Practice Test PDF https://www.easy-quizzz.com/gb/ Explanation: The component being plated must be the cathode, connected to the negative terminal, because copper ions gain electrons there and are reduced to copper metal. The copper electrode acts as the anode, where copper dissolves to replenish copper ions in the solution. Question 5 A student states: “In an aqueous sodium chloride electrolysis cell, the electric current is carried through the solution by electrons moving between the electrodes.” Which correction is most accurate? Options: A. Electrons carry the current through the solution, while sodium and chloride ions carry it through the wires B. Sodium ions carry the current through the solution, while chloride ions carry it through the external circuit C. Positive and negative ions carry the current through the solution, while electrons carry it through the external circuit D. Chloride ions carry the current through the solution, while sodium ions carry it through the external circuit Answer: C Explanation: In the electrolyte, charged ions migrate and transport charge: cations move towards the cathode and anions towards the anode. In the metallic wires and electrodes, charge is transported by electrons. The types of charge carriers therefore change at the electrode–electrolyte interface. Question 6 During setup of an electrolytic cell, a technician connects the negative terminal of a direct-current power supply to one electrode and the positive terminal to the other. Which statement correctly describes the electrode connected to the negative terminal? Options: A. It is the anode, where oxidation takes place B. It is the anode, where reduction takes place C. It is the cathode, where reduction takes place D. It is the cathode, where oxidation takes place Answer: C Explanation: Certifications Certifications Electrolysis Practice Test PDF https://www.easy-quizzz.com/gb/ In an electrolytic cell, the external power supply drives a non-spontaneous reaction. Electrons are supplied to the negative electrode, making it the cathode, where reduction occurs. Oxidation occurs at the positive anode. Question 7 Molten lead(II) bromide is electrolysed using inert electrodes. Which combination correctly describes the products and the electrode reactions? Options: A. Lead forms at the anode by oxidation, while bromine forms at the cathode by reduction B. Lead forms at the cathode by reduction, while bromine forms at the anode by oxidation C. Bromine forms at both electrodes because bromide ions are present in the electrolyte D. Lead(II) bromide remains unchanged because its ions cannot move when molten Answer: B Explanation: In the molten compound, Pb2+ ions move to the cathode and gain electrons to form lead: Pb2+ + 2e Pb. Br ions move to the anode and lose electrons to form bromine: 2Br Br2 + 2e. The other options reverse the electrode processes or incorrectly assume that molten ions cannot move. Question 8 An aqueous solution of copper(II) sulfate is electrolysed using inert electrodes. Which pair of products is expected at the cathode and anode, respectively? Options: A. Hydrogen and sulfur dioxide B. Copper and oxygen C. Copper and sulfur dioxide D. Hydrogen and oxygen Answer: B Explanation: At the cathode, Cu² ions are preferentially reduced to copper because copper is less reactive than hydrogen. At the anode, sulfate ions are not readily discharged, so hydroxide ions from water are oxidised to form oxygen. Question 9 Certifications Certifications Electrolysis Practice Test PDF https://www.easy-quizzz.com/gb/ A student electrolyses aqueous copper(II) sulfate using inert electrodes. Which combination correctly gives the electrode half-equations and the overall ionic equation? Options: A. Cathode: Cu Cu² + 2e; anode: 2HO + 2e H + 2OH; overall: 2Cu + 2HO 2Cu² + H + 2OH B. Cathode: Cu² + 2e Cu; anode: 4OH O + 2HO + 4e; overall: 2Cu² + 2HO 2Cu + O + 4H C. Cathode: 2HO O + 4H + 4e; anode: Cu² + 2e Cu; overall: 2Cu² + 2HO 2Cu + O + 4H D. Cathode: Cu² + 2e Cu; anode: 2Cl Cl + 2e; overall: Cu² + 2Cl Cu + Cl Answer: B Explanation: At the cathode, copper(II) ions gain electrons and are reduced to copper. At the inert anode, hydroxide ions are oxidised to oxygen. The half-equations balance to give 2Cu² + 2HO 2Cu + O + 4H. Chloride ions are not present in copper(II) sulfate solution, so the chlorine equation is not applicable. Question 10 A metal is deposited during electrolysis using a current of 1.5 A for 20 minutes. If the same electrolyte is electrolysed with a current of 3.0 A for 10 minutes, how will the mass of metal deposited compare, assuming the current efficiency is unchanged? Options: A. It will be half as great B. It will be twice as great C. It will be the same D. It will be four times as great Answer: C Explanation: Faraday's first law states that the mass deposited is proportional to the quantity of electricity passed, Q = It. In the first case, Q = 1.5 × 20; in the second, Q = 3.0 × 10. The charges are equal, so the deposited masses are equal. Would you like to see more? 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