2020 P1 Q26 - Deducing Functional Groups that React with NaOH

Let's take a look at 2020 A Levels H2 Chemistry Paper 1 Question 26.

2020 p1 q26 question

We are required to deduce which functional groups in compound X will react with cold NaOH(aq).

Let's identify the functional groups present first.

2020 p1 q26 identify functional groups

We have the following FGs present in X:
- alcohol
- amide
- phenol

Next let us consider the reaction with cold NaOH(aq).

This should only be limited to acid-base reaction or neutralisation due to the cold conditions.

So we can consider if each functional group will undergo neutralisation with NaOH.

2020 p1 q26 deduce which FG reacts with NaOH

1. Alcohols are neutral hence no reaction with NaOH.

2. Amides are neutral hence no reaction with NaOH, cold.

However amides can be hydrolysed with NaOH(aq) with heating to form salt of acid and amine.

3. Phenols are acidic enough to react with NaOH.

So out of the 3 functional groups, only option 3 (phenol) will react.

2020 p1 q26 answer

Hence the answer to this question is option D.

Check out the following video to compare acidity of different functional groups in organic chem.

Topic: Alcohols, Organic Chemistry, A Level Chemistry, Singapore

Back to list of questions for 2020 A Level H2 Chemistry Paper 1.

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