IB Chemistry HL 3.4.9 Nucleophilic Substitution Mechanisms Question Bank

Practise IB Chemistry HL 3.4.9 with questions comparing SN1 and SN2 steps, stereospecificity and leaving-group effects.

Exam points

associate primary substrates with SN2 and tertiary substrates with SN1 in the syllabus model
draw an SN2 transition state with partial bonds, charges and stereochemical inversion
draw SN1 ionisation to a carbocation followed by nucleophilic attack in a second step

[Maximum number: 1]

Organic compounds have many industrial applications.

1-Bromobutane reacts with aqueous sodium hydroxide, NaOH(aq), to form butan-1-ol.

Draw the transition state produced in this mechanism.

Figure for Answer to Question 3.4.9 (HL)—Nucleophilic substitution mechanisms question 1 — IB Chemistry HL

Charge and square bracket must be included.

Accept two partial negative charges on Br AND O in HO, shown either as $\delta-$ or $\frac{1}{2-}$ .

Partial bonds from HO to C AND from C to Br must be shown.

Accept any angle for the partial bonds.

Accept carbocation, or a valid transition state, if $S_{N} 1$ named in (d)(l).

Accept any correct representation including skeletal structures.

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3.4.9 (HL)—Nucleophilic substitution mechanisms question 1