A technician pushes two graphite electrodes into solid sodium nitrate crystals and connects them to a low-voltage direct current supply. An ammeter in the circuit reads zero.
Which statement explains why no current passes through the sodium nitrate?
Its ions are in fixed positions and cannot move
It is made of uncharged molecules, not ions
Graphite electrodes cannot conduct electricity
The voltage is too low to split it into ions
98 exam-style questions on OCR GCSE Chemistry 3.4 Electrolysis, covering 3.4.1 Products formed at the electrodes in electrolysis and 3.4.2 The technique of electrolysis. Each one has a worked solution and a mark scheme showing where the marks go.