DP Chemistry (first assessment 2025)
Question 20N.1A.SL.TZ0.25
Date | November 2020 | Marks available | [Maximum mark: 1] | Reference code | 20N.1A.SL.TZ0.25 |
Level | SL | Paper | 1A | Time zone | TZ0 |
Command term | State | Question number | 25 | Adapted from | N/A |
25.
[Maximum mark: 1]
20N.1A.SL.TZ0.25
Which molecule will decolorize bromine water in the dark?
A. cyclohexane
B. hexane
C. hex-1-ene
D. hexan-1-ol
[1]
Markscheme
C
Examiners report
Two-thirds of candidates knew that hex-1-ene would decolourize bromine water in the dark.
Syllabus sections
Reactivity 3. What are the mechanisms of chemical change? » Reactivity 3.4—Electron-pair sharing reactions » Reactivity 3.4.5—Alkenes are susceptible to electrophilic attack because of the high electron density of the carbon–carbon double bond. These reactions lead to electrophilic addition. Deduce equations for the reactions of alkenes with water, halogens, and hydrogen halides.