Since ancient times, the bark of willow trees has been used for pain relief - VCE - SSCE Chemistry - Question 8 - 2010 - Paper 1
Question 8
Since ancient times, the bark of willow trees has been used for pain relief. In the 19th century, chemists isolated the active compound, salicin, from the bark. This... show full transcript
Worked Solution & Example Answer:Since ancient times, the bark of willow trees has been used for pain relief - VCE - SSCE Chemistry - Question 8 - 2010 - Paper 1
Step 1
What type of linkage is circled in the structure of salicin?
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Answer
The type of linkage circled in the structure of salicin is an ester linkage.
Step 2
In step 1, salicylic alcohol and another compound is produced.
i. What group of biomolecules does this other compound belong to?
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The other compound produced in step 1 belongs to the group of biomolecules known as carbohydrates.
Step 3
ii. The structure of this other compound is not complete. Write the formula of the atom or group of atoms represented by A in the reaction scheme above.
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The atom or group of atoms represented by A in the reaction scheme is -OH (a hydroxyl group).
Step 4
Step 2 involves the conversion of salicylic alcohol into salicylic acid.
i. What type of reaction is step 2?
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Step 2 is an oxidation reaction, where salicylic alcohol is converted to salicylic acid.
Step 5
ii. Suggest a suitable reagent to carry out the reaction.
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A suitable reagent to carry out the reaction is potassium dichromate (K₂Cr₂O₇) in an acidic medium.
Step 6
Step 3 requires sulfuric acid catalyst and another reagent. Name this reagent.
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The other reagent required in Step 3 is likely sodium hydroxide (NaOH).
Step 7
Draw the structure of product B.
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The structure of product B is as follows:
O
||
R-C-OH
\ /
R'
Where R represents a hydrocarbon tail and R' is a substituted group.
