DP Chemistry (last assessment 2024)
Question 19M.2.sl.TZ2.b(ii)
Date | May 2019 | Marks available | [Maximum mark: 1] | Reference code | 19M.2.sl.TZ2.b(ii) |
Level | sl | Paper | 2 | Time zone | TZ2 |
Command term | Compare | Question number | b(ii) | Adapted from | N/A |
b(ii).
[Maximum mark: 1]
19M.2.sl.TZ2.b(ii)
Ethyne, C2H2, reacts with oxygen in welding torches.
Compare, giving a reason, the length of the bond between the carbon atoms in ethyne with that in ethane, C2H6.
[1]
Markscheme
«ethyne» shorter AND a greater number of shared/bonding electrons
OR
«ethyne» shorter AND stronger bond [✔]
Examiners report
A very well answered question. The vast majority of candidates understood that triple bonds are stronger than single bonds and result in a shorter bond length. It was disappointing, however, to see a considerable number of candidates stating that ethane has a double bond.
