DP Chemistry (last assessment 2024)
Question 17N.2.hl.TZ0.8e
| Date | November 2017 | Marks available | [Maximum mark: 4] | Reference code | 17N.2.hl.TZ0.8e |
| Level | hl | Paper | 2 | Time zone | TZ0 |
| Command term | Explain | Question number | e | Adapted from | N/A |
e.
[Maximum mark: 4]
17N.2.hl.TZ0.8e
The reactivity of organic compounds depends on the nature and positions of their functional groups.
(e)
Explain the mechanism of the reaction between 2-bromo-2-methylpropane, (CH3)3CBr, and aqueous sodium hydroxide, NaOH (aq), using curly arrows to represent the movement of electron pairs.
[4]
Markscheme
curly arrow showing Br– leaving
representation of tertiary carbocation
curly arrow going from lone pair/negative charge on O in –OH to C+
formation of (CH3)3COH AND Br–
Do not accept curly arrow originating from C of C–Br bond.
Do not accept arrow originating on H in –OH.
Accept Br– anywhere on product side in the reaction scheme.
Award [2 max] for an SN2 type mechanism.
