DP Chemistry (first assessment 2025)
Question 22M.2.SL.TZ1.1d(iii)
| Date | May 2022 | Marks available | [Maximum mark: 2] | Reference code | 22M.2.SL.TZ1.1d(iii) |
| Level | SL | Paper | 2 | Time zone | TZ1 |
| Command term | Deduce, Justify | Question number | d(iii) | Adapted from | N/A |
d(iii).
[Maximum mark: 2]
22M.2.SL.TZ1.1d(iii)
(d(iii))
Deduce, giving reasons, whether the reaction of magnesium nitride with water is an acid–base reaction, a redox reaction, neither or both.
[2]
Markscheme
Acid–base:
yes AND N3- accepts H+/donates electron pair«s»
OR
yes AND H2O loses H+ «to form OH-»/accepts electron pair«s» ✔
Redox:
no AND no oxidation states change ✔
Accept “yes AND proton transfer takes place”
Accept reference to the oxidation state of specific elements not changing.
Accept “not redox as no electrons gained/lost”.
Award [1 max] for Acid–base: yes AND Redox: no without correct reasons, if no other mark has been awarded
Examiners report
Probably only about 10% could explain why this was an acid-base reaction. Rather more made valid deductions about redox, based on their answer to the previous question.
Syllabus sections
Reactivity 3. What are the mechanisms of chemical change? » Reactivity 3.2—Electron transfer reactions » Reactivity 3.2.1—Oxidation and reduction can be described in terms of electron transfer, change in oxidation state, oxygen gain/loss or hydrogen loss/gain. Deduce oxidation states of an atom in a compound or an ion. Identify the oxidized and reduced species and the oxidizing and reducing agents in a chemical reaction.