DP Chemistry (last assessment 2024)
Question 19M.2.sl.TZ2.c(i)
| Date | May 2019 | Marks available | [Maximum mark: 1] | Reference code | 19M.2.sl.TZ2.c(i) |
| Level | sl | Paper | 2 | Time zone | TZ2 |
| Command term | State | Question number | c(i) | Adapted from | N/A |
c(i).
[Maximum mark: 1]
19M.2.sl.TZ2.c(i)
Ethyne, C2H2, reacts with oxygen in welding torches.
Ethyne reacts with steam.
C2H2 (g) + H2O (g) → C2H4O (g)
Two possible products are:
Product A contains a carbon–carbon double bond. State the type of reactions that compounds containing this bond are likely to undergo.
[1]
Markscheme
«electrophilic» addition/A«E» [✔]
Note: Accept “polymerization”.
Examiners report
About 60 % of the candidates stated “addition” as the type of reactions that compounds containing carbon-carbon double bonds underwent. It was disappointing to see a variety of answers including substitution, condensation and combustion showing a total lack of understanding. Some candidates gave specific types such as "bromination" or “hydration” which did not receive the mark.
