The polymer polylactic acid, PLA, shown above, is used to make soluble stitches which are absorbed by the body following surgery - VCE - SSCE Chemistry - Question 4 - 2009 - Paper 1
Question 4
The polymer polylactic acid, PLA, shown above, is used to make soluble stitches which are absorbed by the body following surgery.
Other than the peak given by the T... show full transcript
Worked Solution & Example Answer:The polymer polylactic acid, PLA, shown above, is used to make soluble stitches which are absorbed by the body following surgery - VCE - SSCE Chemistry - Question 4 - 2009 - Paper 1
Step 1
one set of peaks in the 1H NMR
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Answer
This option suggests that the monomer structure would result in a single set of NMR peaks, indicating identical environments for hydrogen atoms. However, PLA consists of repeating units that are likely to create multiple environments.
Step 2
two sets of peaks in the 1H NMR
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Answer
This option implies there would be two distinct environments for hydrogen atoms, which does not accurately represent the structure of PLA.
Step 3
three sets of peaks in the 1H NMR
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Answer
This option considers that there would be three distinct sets of peaks in the NMR spectrum. However, upon analyzing the structure, it is clear that more than three environments are present.
Step 4
four sets of peaks in the 1H NMR
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Answer
This is the correct option, as the repeating units of PLA generate four distinct environments for hydrogen atoms in the NMR spectrum due to the different chemical surroundings of the hydrogen atoms connected to the carbons in the polymer chain.
