DP Chemistry (last assessment 2024)
Question 22M.2.sl.TZ2.4d(iii)
| Date | May 2022 | Marks available | [Maximum mark: 1] | Reference code | 22M.2.sl.TZ2.4d(iii) |
| Level | sl | Paper | 2 | Time zone | TZ2 |
| Command term | State | Question number | d(iii) | Adapted from | N/A |
d(iii).
[Maximum mark: 1]
22M.2.sl.TZ2.4d(iii)
Carbon forms many compounds.
But-2-ene reacts with hydrogen bromide.
(d(iii))
State the type of reaction.
[1]
Markscheme
«electrophilic» addition/EA ✔
Do not accept nucleophilic or free radical addition.
Examiners report
Well answered. 60% of candidates identified the type of reaction between but-2-ene and HBr, some of them including the term “electrophilic”. ECF was generously awarded when substitution was stated based on the equation where H2 was produced in part (ii). Candidates lost the mark if they only stated “hydrobromination” without mentioning addition. Some candidates lost the mark for stating “nucleophilic” or “free radical” addition.
