| Date | November 2017 | Marks available | 2 | Reference code | 17N.3.hl.TZ0.22 |
| Level | HL | Paper | 3 | Time zone | TZ0 |
| Command term | Describe | Question number | 22 | Adapted from | N/A |
Question
Ibuprofen and paracetamol are mild analgesics. One of the IR spectra below belongs to ibuprofen and the other to paracetamol. The structures of both compounds are given in section 37 of the data booklet.
Both spectra show a peak at wavenumber 1700 cm–1. Identify the bond responsible for this peak.
Deduce which spectrum belongs to paracetamol, giving two reasons for your choice. Use section 26 of the data booklet.
Describe how mild analgesics function.
Markscheme
C=O
Accept “carbonyl”.
X (must be identified) AND
Any two of:
For X:
N–H «absorption» AND at 3300 – 3500 «cm–1» ✔
O–H «absorption» in phenol AND at 3200 – 3600 «cm–1» ✔
absence of OH «absorption» in carboxylic acid AND 2500 – 3000 «cm–1»
Accept any specific wavenumber in the range 3300–3380 «cm–1» for M1.
Accept any specific wavenumber in the range 3100–3200 «cm–1».
Award [1 max] if Y is incorrectly identified for paracetamol but if a correct reason/reasons is/are given for the bond absorption(s).
[Max 2 Marks]
prevents/interferes with the production of prostaglandins
OR
prevents/interferes with the production of substances responsible for inflammation/pain/fever at the site of injury/source of pain
