DP Chemistry (first assessment 2025)
Question 19M.2.HL.TZ1.1c(ii)
| Date | May 2019 | Marks available | [Maximum mark: 2] | Reference code | 19M.2.HL.TZ1.1c(ii) |
| Level | HL | Paper | 2 | Time zone | TZ1 |
| Command term | Draw | Question number | c(ii) | Adapted from | N/A |
c(ii).
[Maximum mark: 2]
19M.2.HL.TZ1.1c(ii)
(c(ii))
1,4-dimethylbenzene reacts as a substituted alkane. Draw the structures of the two products of the overall reaction when one molecule of bromine reacts with one molecule of 1,4-dimethylbenzene.
[2]
Markscheme
[✔]
HBr [✔]
Note: Accept condensed formulae, such as CH3C6H4CH2Br.
Accept skeletal structures.
Examiners report
Very few students gained 2 marks finding hard to apply their knowledge of free radical substitution to a benzene containing compound. Many thought that the bromine will attach to the benzene ring or would substitute the alkyl group twice and not produce HBr.
Syllabus sections
Reactivity 3. What are the mechanisms of chemical change? » Reactivity 3.4—Electron-pair sharing reactions » Reactivity 3.4.13—Electrophilic substitution reactions include the reactions of benzene with electrophiles. Describe and explain the mechanism of the reaction between benzene and a charged electrophile, E+.