DP Chemistry (first assessment 2025)
Question 22M.1A.SL.TZ2.26
| Date | May 2022 | Marks available | [Maximum mark: 1] | Reference code | 22M.1A.SL.TZ2.26 |
| Level | SL | Paper | 1A | Time zone | TZ2 |
| Command term | State | Question number | 26 | Adapted from | N/A |
26.
[Maximum mark: 1]
22M.1A.SL.TZ2.26
Which is a homologous series?
A. C2H4, C3H5, C4H6
B. C2H2, C3H4, C4H6
C. C2H2, C2H4, C2H6
D. C2H2, C4H4, C6H6
[1]
Markscheme
B
Examiners report
45% of the candidates identified the members of the same homologous series (ethyne, propyne and butyne). The most commonly chosen distractor included the compounds C2H2, C4H4 and C6H6. The question had good discrimination between high-scoring and low-scoring candidates.
Syllabus sections
Structure 3. Classification of matter » Structure 3.2—Functional groups: Classification of organic compounds » Structure 3.2.3—A homologous series is a family of compounds in which successive members differ by a common structural unit, typically CH2. Each homologous series can be described by a general formula. Identify the following homologous series: alkanes, alkenes, alkynes, halogenoalkanes, alcohols, aldehydes, ketones, carboxylic acids, ethers, amines, amides and esters.