DP Chemistry (first assessment 2025)
Question 22M.2.HL.TZ1.b(ii)
| Date | May 2022 | Marks available | [Maximum mark: 1] | Reference code | 22M.2.HL.TZ1.b(ii) |
| Level | HL | Paper | 2 | Time zone | TZ1 |
| Command term | Draw | Question number | b(ii) | Adapted from | N/A |
b(ii).
[Maximum mark: 1]
22M.2.HL.TZ1.b(ii)
Draw the structural formula of the carbocation intermediate produced when this electrophile attacks benzene.
[1]
Markscheme
Accept any of the five structures.
Do not accept structures missing the positive charge.
Examiners report
Again, many had difficulty drawing the structural formula of the carbocation intermediate produced in the reaction.
Syllabus sections
Reactivity 3. What are the mechanisms of chemical change? » Reactivity 3.4—Electron-pair sharing reactions » Reactivity 3.4.12—The relative stability of carbocations in the addition reactions between hydrogen halides and unsymmetrical alkenes can be used to explain the reaction mechanism. Predict and explain the major product of a reaction between an unsymmetrical alkene and a hydrogen halide or water.
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+.