DP Chemistry (first assessment 2025)
Question 22N.1A.SL.TZ0.26
| Date | November 2022 | Marks available | [Maximum mark: 1] | Reference code | 22N.1A.SL.TZ0.26 |
| Level | SL | Paper | 1A | Time zone | TZ0 |
| Command term | State | Question number | 26 | Adapted from | N/A |
26.
[Maximum mark: 1]
22N.1A.SL.TZ0.26
Which conditions best favour oxidation of primary alcohols directly to carboxylic acids?
A. Excess acidified potassium dichromate (VI) and distillation
B. Excess acidified potassium dichromate (VI) and reflux
C. Few drops of acidified potassium dichromate (VI) and distillation
D. Few drops of acidified potassium dichromate (VI) and reflux
[1]
Markscheme
B
Examiners report
51% of the candidates identified the conditions that favour the oxidation of primary alcohols directly to carboxylic acids. The question had good discrimination between high-scoring and low-scoring candidates.
Syllabus sections
Reactivity 3. What are the mechanisms of chemical change? » Reactivity 3.2—Electron transfer reactions » Reactivity 3.2.9—Functional groups in organic compounds may undergo oxidation. Deduce equations to show changes in the functional groups during oxidation of primary and secondary alcohols, including the two-step reaction in the oxidation of primary alcohols.
Reactivity 3. What are the mechanisms of chemical change? » Reactivity 3.1—Proton transfer reactions » Reactivity 3.1.16—A buffer solution is one that resists change in pH on the addition of small amounts of acid or alkali. Describe the composition of acidic and basic buffers and explain their actions.