| Date | May 2016 | Marks available | 1 | Reference code | 16M.3.hl.TZ0.13 |
| Level | HL | Paper | 3 | Time zone | TZ0 |
| Command term | Identify | Question number | 13 | Adapted from | N/A |
Question
Spinach is an excellent source of vitamins A and C.
Identify one structural characteristic in vitamins A and D which makes them more similar to each other than they are to vitamin C using section 35 of the data booklet.
The pigments from spinach were separated using chromatography. Identify Z by calculating its Rf value and using the data table.
Rf:
Z:
Markscheme
A and D have one/few polar/hydroxyl/OH groups «but C has many of those»
OR
A and D have hydrocarbon/six-membered «carbon» rings «but C has heterocyclic/five-membered ring»
OR
A and D have long hydrocarbon chains/consist of mainly non-polar components
Accept other valid similarities or differences.
Accept “hydroxy/alcohol” but not “hydroxide” for “hydroxyl”.
0.47 AND chlorophyll b
Accept any Rf value in the range 0.44–0.50.
