Question 22M.2.sl.TZ1.d(iii)
| Date | May 2022 | Marks available | [Maximum mark: 2] | Reference code | 22M.2.sl.TZ1.d(iii) |
| Level | sl | Paper | 2 | Time zone | TZ1 |
| Command term | Deduce, Justify | Question number | d(iii) | Adapted from | N/A |
When heated in air, magnesium ribbon reacts with oxygen to form magnesium oxide.
The presence of magnesium nitride can be demonstrated by adding water to the product. It is hydrolysed to form magnesium hydroxide and ammonia.
Deduce, giving reasons, whether the reaction of magnesium nitride with water is an acid–base reaction, a redox reaction, neither or both.
[2]
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
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.
