A Level Chemistry 2017 Paper 1 Question 21 Solution - Exclusive

In this exclusive video we want to discuss the suggested solution for A Levels Chemistry (H2 Chemistry) 2017 Paper 1 Question 21.

Let's take a look at this question:

2017 H2 Chem P1 Q21 question

The topic tested in this question is on basicity of Nitrogen compounds in Organic Chemistry.

The basicity of nitrogen compounds is directly related to lone pair availability on nitrogen. The more available the lone pair, the stronger the base. For a more detailed comparison you can check out my video on Basicity of Nitrogen Compounds.

There are only 3 compounds in this question to consider so let's discuss their lone pair availability in detail.

1. Amine Basicity

Electron donating R groups will increase lone pair availability which makes amines better lone pair donors. This makes amines more basic than ammonia.

2017 H2 Chem P1 Q21 amine basicity

2. Phenylamine Basicity

Lone pair on nitrogen will be delocalised into the benzene ring which makes it less available for donation. This makes phenylamine less basic than ammonia which in turn makes it less basic than amines.

2017 H2 Chem P1 Q21 phenylamine basicity

3. Amide Basicity

Lone pair on nitrogen is delocalised extensively into the acyl carbon. The lone pair is not used for donation hence amides are neutral and the least basic amongst all nitrogen compounds.

2017 H2 Chem P1 Q21 amide basicity

Finally we can rank the 3 compounds in order of increasing basicity and compare the options to determine that the answer to this question is A.

2017 H2 Chem P1 Q21 compare basicity and answer

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

Topic: Basicity of Nitrogen Compounds, Organic Chemistry, A Level Chemistry, Singapore

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