Substance Key properties diamond extremely hard, does not conduct graphite conducts electricity, high melting point poly(ethene) soft, does not conduct The ...
Question 1 Report
| Substance | Key properties |
|---|---|
| diamond | extremely hard, does not conduct |
| graphite | conducts electricity, high melting point |
| poly(ethene) | soft, does not conduct |
The table gives the key properties of three substances. Use the data to choose the substance that is most suitable for making the electrodes used during electrolysis.
Answer Details
An electrode must carry a current and survive the heat and the electrolyte without melting or reacting, so graphite is the choice. The table lists it as the only substance that both conducts electricity and has a high melting point. Each carbon in graphite bonds to only three others, leaving one delocalised electron per atom free to move through the layers and carry the charge.
Diamond is also giant covalent and heat resistant, but every outer electron is locked into a bond, so it cannot conduct. Poly(ethene) is soft and non-conducting and would melt, and carbon dioxide is a gas, not a solid electrode material.
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