What would happen with non-electrolytes?
2 marks · NormalExplain why potassium iodide (KI) will conduct electricity when molten but not as a solid.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
In the solid, KI's ions cannot move, so electricity cannot pass. When molten, the ions are free to move and carry charge, allowing conduction.
Also accept: Solid KI's ions are fixed in place and can't carry current. Molten KI's ions are free to move, so it conducts electricity.
Common mistakes: Saying solid KI conducts; Not mentioning ion movement
Show mark scheme and worked solution
Marking points
B1 · 1 mark · States ions in solid are not free to move, so no conduction.
B2 · 1 mark · Explains that in the molten state, ions can move and carry current.
Worked solution
In solid KI, the ions are fixed in place in the lattice and cannot move to carry charge. When molten, the lattice breaks down and the ions are free to move, allowing KI to conduct electricity.