A technician tests calcium chloride using the same direct current power supply and electrodes in each trial.
| Trial | Calcium chloride sample | Current detected | Observation at the negative electrode |
|---|---|---|---|
| A | solid | no | no product forms |
| B | dissolved in water | yes | bubbles of gas form |
| C | molten | yes | a metal forms |
Use the results to explain why only Trial C can be used to extract calcium. Explain why heating calcium oxide with carbon would not be a suitable alternative.
136 exam-style questions on OCR GCSE Chemistry 6.1 Improving processes and products, covering 6.1.1 Extracting metals industrially and by electrolysis, 6.1.2 Life cycle assessment and recycling, 6.1.3 Biological methods of metal extraction, 6.1.4 The Haber process and the production of fertilisers, 6.1.5 Alloys and their uses, 6.1.6 Corrosion and its prevention, 6.1.7 Comparing and selecting materials, and 6.1.8 Industrial conditions, rate and position of equilibrium. Each one has a worked solution and a mark scheme showing where the marks go.