A Level Chemistry 2017 Paper 1 Question 24 Solution - Exclusive

In this exclusive video we want to discuss the suggested solution for A Levels Chemistry (H2 Chemistry) 2017 Paper 1 Question 24.

Let Chemistry Guru, Singapore's top JC Chemistry tuition centre, guide you through this question:

2017 A Level H2 Chemistry P1 Q24 question

The topic tested in this question is on Halogenoalkanes and Alkenes. In particular the reactions of these two functional groups. For a recap, check out these video lessons on alkene reactions and halogenoalkane reactions.

This is an interesting question as we need to consider what other compounds can react with the reagents and conditions specified in the question: aqueous sodium hydroxide.

1. Consider the reaction with reactant 1-bromopropane

2017 A Level H2 Chemistry P1 Q24 consider direct reaction from reactant 1 bromopropane

Apart from the given reaction of 1-bromopropane to form main product propan-1-ol, elimination to form propene, the first by-product, is also possible.

This is because the reagents and conditions for both nucleophilic substitution and elimination are very similar:

Nucleophilic Substitution: NaOH(aq), reflux
Elimination: KOH in ethanol, reflux

There are no straightforward ways to form the second and third by-product from 1-bromopropane.

2. Consider the reaction with main product propan-1-ol

2017 A Level H2 Chemistry P1 Q24 consider reaction from main product propan 1 ol

Again there are no straightforward ways to form the second and third by-product from propan-1-ol.

3. Consider the reaction with by-product propene

2017 A Level H2 Chemistry P1 Q24 consider reaction from byproduct propene

Interestingly we can form the second by-product propan-1,2-diol and third by-product propan-2-ol from propene.

However the reagents and conditions for these conversions is not NaOH(aq), reflux.

Hence we cannot get these two by-products from propene too.

We can now compare the options and decide the answer to this question is option C.

2017 A Level H2 Chemistry P1 Q24 compare options

Check out this video for the full solution and detailed explanation!

Topic: Halogenoalkanes and Alkenes, Organic Chemistry, A Level Chemistry, Singapore

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