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Paracetamol is a commonly used painkiller - VCE - SSCE Chemistry - Question 3 - 2008 - Paper 1
Question 3
Paracetamol is a commonly used painkiller. The equation below shows one method of preparing paracetamol. 4-aminophenol + (Reagent) → Paracetamol In the box provide... show full transcript
Worked Solution & Example Answer:Paracetamol is a commonly used painkiller - VCE - SSCE Chemistry - Question 3 - 2008 - Paper 1
Step 1
In the box provided in the equation above, give the formula of a possible reagent that can be used in this synthesis.
Answer
A possible reagent that can be used in the synthesis of paracetamol from 4-aminophenol is acetic anhydride (C4H6O3). This reagent acts as a acetylating agent, allowing the hydroxyl group of 4-aminophenol to be replaced by an acetyl group, forming paracetamol.
Step 2
On the diagram of a TLC plate below, use a horizontal line to mark the spot where paracetamol would appear in such an analysis.
Answer
On the TLC plate, mark a horizontal line at the position corresponding to Rf = 0.4 from the origin, indicating where paracetamol would appear after the solvent front has moved.
Step 3
Predict whether the Rf value of 4-aminophenol in this analysis is greater or smaller than that of paracetamol, giving a reason for your choice.
Answer
The Rf value of 4-aminophenol is expected to be greater than that of paracetamol. This is because 4-aminophenol adsorbs less strongly to the stationary phase, allowing it to move further up the plate in comparison to paracetamol, which adheres more strongly to the stationary phase.