Being able to answer structural elucidation questions is important if you want to do well for H2 A Level Chemistry. Such questions are often worth many marks.
In this post, let’s look at:
- What is structural elucidation
- What concepts are tested in structural elucidation questions
- How to score
- How to format your answers
- What you need to do well
What is structural elucidation?
Before we go on to look at how to answer structural elucidation questions, let’s first talk about what are structural elucidation question. A structural elucidation question is one in which students are given the various reactions of an unknown compound (or compounds), and asked to deduce the structure of the unknown compound(s).
What concepts are tested in structural elucidation questions?
The main concept that is tested in structural elucidation is reactions of organic compounds. However, students are also tested on isomerism (e.g. compound A rotates plane polarised light – meaning it has a chiral carbon), physical property (e.g. soluble in water etc.) occasionally. Nonetheless, the key concept tested is organic chemistry reactions.
How to score for structural elucidation questions?
To get the marks for structural elucidation question, you first have to look at the question to see what is asked. Only by providing the examiner with what they ask for would you get the marks. Let me explain what I mean.
If the question only ask you to deduce the structure of the compounds, then you will only be given marks for providing the structure of the compounds. No need to explain.
If the question ask you to deduce the structure and explain – then you get generally 1 mark for each structure, and half a mark for each explanation. So when you want to check whether you will get all the points, make sure you write all the structures, and you should have enough deductions made to get the remaining marks.
If the question ask you to deduce and write equations to explain the reactions, the you get generally 1 mark for each structure and 1 mark for each equation.
Format to answer structural elucidation questions that require deduction of structure and explanation
Structural elucidation questions that require students to provide both the structures and the explanation are very common in H2 A Level Chemistry exams.
The format of such answers usually take a table form followed by the structures of the unknown compound.
The statement is simply the “words in the question”, and the deduction is basically what you deductions from those words. Deductions could be about functional groups, structure, etc.
What you need to do well for structural elucidation questions
To do well for structural elucidation questions, students have to
- know the organic reactions well
- be able to work backwards
- know how to answer the question to get the marks
The best way is to practice once you have revised the organic chemistry topics and are familiar with the reactions. Being able to work backwards, and answer well is a matter of practice. See our step-by-step guide on how to answer structural elucidation question using a sample question, to reinforce what you’ve learnt.
- Organic Chemistry Reactions Tested in H2 A Level Chemistry
- Organic Chemistry Reaction Mechanisms
- Organic Chemistry Concept Maps Part 1
- Organic Chemistry Concept Maps Part 2
- Structural Elucidation Questions
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