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In the margarine industry, alkenes are often hydrogenated to convert unsaturated oils into solid fats that have a greater proportion of saturated molecules - HSC - SSCE Chemistry - Question 24 - 2010 - Paper 1
Question 24
In the margarine industry, alkenes are often hydrogenated to convert unsaturated oils into solid fats that have a greater proportion of saturated molecules. (a) Usi... show full transcript
Worked Solution & Example Answer:In the margarine industry, alkenes are often hydrogenated to convert unsaturated oils into solid fats that have a greater proportion of saturated molecules - HSC - SSCE Chemistry - Question 24 - 2010 - Paper 1
Step 1
Using ethene as an example, write an equation for this reaction and state the type of reaction this represents.
Answer
The hydrogenation of ethene can be represented by the following balanced chemical equation:
In this reaction, ethene (C₂H₄) reacts with hydrogen gas (H₂) to form ethane (C₂H₆). This represents an addition reaction, as the hydrogen is being added across the double bond of the alkene.
Step 2
Describe a test that could be used to confirm that all the ethene has been converted.
Answer
A suitable test to confirm the conversion of ethene is to use bromine water.
- Observation: Bromine water is a reddish-brown solution.
- Procedure: If ethene is present, the bromine water will decolourise, turning from brown to colourless. This indicates the presence of ethene.
- Conclusion: The disappearance of the brown colour confirms that all the ethene has reacted, as it reacts with bromine to form a dibromo compound, preventing the colour from remaining.