ElectrolysisIB MYP Chemistry: Mind map

Exam questions on Electrolysis

1. A technician in a school laboratory in Nairobi electrolyses molten lead(II) bromide, PbBr₂, using inert graphite electrodes inside a fume cupboard.
   Write the half-equation for the change at the anode.2 marks
2. A student electrolyses blue copper(II) sulfate solution for 20 minutes using inert graphite electrodes. A pink-brown solid coats the cathode, bubbles of a colourless gas form at the anode and relight a glowing splint, and the blue colour of the solution fades slightly.
   The student now plans to investigate how the size of the current affects the mass of copper deposited at the cathode in 20 minutes. Identify the independent variable and the dependent variable.2 marks
3. A chemical plant in Jubail, Saudi Arabia, electrolyses concentrated sodium chloride solution (brine) using inert electrodes. The process makes three useful products.
   Explain why hydrogen, and not sodium, forms at the cathode.3 marks