DP Chemistry (last assessment 2024)
Question 18N.3.sl.TZ0.4c
| Date | November 2018 | Marks available | [Maximum mark: 2] | Reference code | 18N.3.sl.TZ0.4c |
| Level | sl | Paper | 3 | Time zone | TZ0 |
| Command term | Predict | Question number | c | Adapted from | N/A |
c.
[Maximum mark: 2]
18N.3.sl.TZ0.4c
While heating solid cholesteryl benzoate, Reinitzer discovered the liquid crystal phase.
(c)
Arc discharge, consisting of two inert metal electrodes in a liquid solvent, is one method of producing carbon nanotubes (CNTs).
Predict, giving a reason, the electrode at which the solvent cyclohexane, C6H12, will decompose to form CNTs.
[2]
Markscheme
«average» oxidation state of C in C6H12/cyclohexane = –2 AND in CNTs = 0
OR
oxidation state of C in CNTs is higher than in C6H12/cyclohexane
OR
loss of H’s/hydrogens ✔
«oxidation at» anode/positive/+ «electrode» ✔
Accept “oxidation number” for “oxidation state”.
