DP Chemistry (last assessment 2024)
Question 20N.3.sl.TZ0.14c(i)
| Date | November 2020 | Marks available | [Maximum mark: 2] | Reference code | 20N.3.sl.TZ0.14c(i) |
| Level | sl | Paper | 3 | Time zone | TZ0 |
| Command term | State and explain | Question number | c(i) | Adapted from | N/A |
c(i).
[Maximum mark: 2]
20N.3.sl.TZ0.14c(i)
Consider the structures of medicinal molecules in section 37 of the data booklet.
(c(i))
State and explain the relative solubility of codeine in water compared to morphine and diamorphine.
[2]
Markscheme
codeine less soluble «in water» than morphine AND more soluble than diamorphine
OR
morphine > codeine > diamorphine «in terms of solubility in water» ✔
more/stronger/greater hydrogen/H bonding «due to more hydroxyl groups leads to greater solubility» ✔
Examiners report
M1 was correctly presented but most students focused on the polarity of the molecules and presented long arguments where intermolecular forces were ignored. The concept of water solubility and hydrogen bonding was largely ignored.
