Question 1: Aqueous electrolysis involves passing an electric current through an aqueous solution to cause chemical changes at the electrodes. It is used to extract elements and produce chemicals. Explain in your own words the basic principle behind electrolysis in aqueous solutions.

Answer: Electrolysis in aqueous solutions uses an electric current to drive non-spontaneous chemical reactions, causing ions in the solution to migrate to electrodes where they are reduced or oxidised.

Question 1: During aqueous electrolysis of sodium chloride solution, what are the products formed at the cathode and anode? Provide the names and relevant ions involved.

Answer: At the cathode, sodium metal or hydrogen gas can form depending on conditions; typically, hydrogen gas is produced from H+ ions. At the anode, chlorine gas is produced from Cl- ions.

Question 2: Explain why water can be electrolysed along with other ions in solution, and how this affects the products formed during electrolysis.

Answer: Water can be electrolysed because it ionises slightly to produce H+ and OH- ions, which can be reduced or oxidised. This affects the products, as sometimes water's ions are reduced or oxidised instead of the other ions present.

Question 1: Calculate the volume of hydrogen gas produced at the cathode when 2 moles of electrons are passed through an aqueous solution. (Use 1 mole of electrons produces 1 mole of H2).

Answer: 0.0448 cubic metres (or 44.8 litres).

Question 2: If a current of 3 amperes is passed through an aqueous solution for 10 minutes, how many moles of electrons have been transferred? (Use Q = I × t, where Q is charge in coulombs, I is current, t is time in seconds).

Answer: 18 moles of electrons.

Question 1: Describe a typical setup for conducting aqueous electrolysis in a school laboratory, including the main components involved.

Answer: A typical setup includes a power supply, two electrodes (usually inert like platinum or graphite), an electrolyte solution, and connecting wires.

Question 2: List two safety precautions students should observe when performing aqueous electrolysis experiments.

Answer: Wearing safety goggles and handling electrical equipment carefully to prevent short circuits or shocks.

Question 1: In an industrial process, aqueous electrolysis is used to produce aluminium from aluminium oxide. Briefly explain how electrolysis is essential in this process.

Answer: Electrolysis is used to break down aluminium oxide into aluminium metal and oxygen gas, as aluminium cannot be extracted by reduction due to its high melting point.

Question 2: A researcher observes that during the electrolysis of a solution, the amount of gas produced at the electrodes does not match the expected calculations. Suggest two reasons why this discrepancy might occur.

Answer: Possible reasons include side reactions occurring at the electrodes, incomplete electrolysis due to insufficient voltage, impurities in the solution, or measurement errors.