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Question 18N.2.hl.TZ0.c

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Date November 2018 Marks available [Maximum mark: 4] Reference code 18N.2.hl.TZ0.c
Level hl Paper 2 Time zone TZ0
Command term Explain Question number c Adapted from N/A
c.
[Maximum mark: 4]
18N.2.hl.TZ0.c

Halogenoalkanes undergo nucleophilic substitution reactions with sodium hydroxide.

Explain the mechanism of the reaction between 1-bromopropane with aqueous sodium hydroxide using curly arrows to represent the movement of electron pairs.

[4]

Markscheme

curly arrow going from lone pair/negative charge on O in HO– to C ✔

curly arrow showing Br leaving ✔

representation of transition state showing negative charge, square brackets and partial bonds ✔

formation of organic product CH3CH2CH2OH AND Br– ✔

 

Do not allow curly arrow originating on H in HO–.

Accept curly arrow either going from bond between C and Br to Br in 1-bromopropane or in the transition state.

Do not penalize if HO and Br are not at 180° to each other.

Do not award M3 if OH–C bond is represented.

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