Photo AI
Ethanol reacts with potassium cyanide, followed by dilute acid, to form 2-hydroxypropanenitrile - AQA - A-Level Chemistry - Question 4 - 2019 - Paper 3
Question 4
Ethanol reacts with potassium cyanide, followed by dilute acid, to form 2-hydroxypropanenitrile. Name the mechanism for the reaction between potassium cyanide and e... show full transcript
Worked Solution & Example Answer:Ethanol reacts with potassium cyanide, followed by dilute acid, to form 2-hydroxypropanenitrile - AQA - A-Level Chemistry - Question 4 - 2019 - Paper 3
Step 1
Step 2
Step 3
Explain how the structure of ethanol leads to the formation of two isomers.
Answer
Ethanol has a chiral center at the carbon atom attached to the hydroxyl group and the hydrogen. This allows for two different configurations (R and S forms) as the cyanide ion can attack from either side, leading to the formation of two isomeric products.
Step 4
Draw 3D representations of the two isomers to show the relationship between them.
Answer
The 3D structures of the two isomers are as follows:
- (R)-2-Hydroxypropanenitrile:
- The -OH group is oriented upwards on the chiral carbon.
- The CN group is oriented downwards.
- (S)-2-Hydroxypropanenitrile:
- The -OH group is oriented downwards on the chiral carbon.
- The CN group is oriented upwards.
The two isomers are mirror images of each other, which can be represented by proper 3D diagrams with wedges and dashed bonds for clarity.
Step 5
Step 6
Draw a section of the polymer polyacrylonitrile, showing three repeating units.
Answer
The section of the polymer polyacrylonitrile can be represented as follows:
[-C-N≡C-CH₂-]n
This represents three repeating units in polyacrylonitrile, where the polymer backbone consists of alternating carbon and nitrogen atoms.