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This question is about 2-bromopropane - AQA - A-Level Chemistry - Question 5 - 2020 - Paper 2
Question 5
This question is about 2-bromopropane. 1. Define the term electronegativity. 2. Explain the polarity of the C–Br bond in 2-bromopropane. Electronegativity ______... show full transcript
Worked Solution & Example Answer:This question is about 2-bromopropane - AQA - A-Level Chemistry - Question 5 - 2020 - Paper 2
Step 1
Step 2
Explain the polarity of the C–Br bond in 2-bromopropane.
Answer
The C–Br bond in 2-bromopropane is polar because bromine is more electronegative than carbon. This means that bromine attracts the bonding electrons more strongly, resulting in a partial negative charge on bromine ( ext{Br}^ ext{-}) and a partial positive charge on carbon ( ext{C}^ ext{+}).
Step 3
Outline the mechanism for the reaction of 2-bromopropane with an excess of ammonia.
Answer
The mechanism involves nucleophilic substitution where:
- The lone pair of electrons on the nitrogen atom of ammonia attacks the carbon atom bonded to bromine, forming an intermediate.
- A curly arrow is drawn from the bond between C and Br to Br, indicating the breaking of the bond.
- The intermediate undergoes loss of a hydrogen atom, resulting in the final amine product.
Step 4
Draw the skeletal formula of the main organic species formed in the reaction between a large excess of 2-bromopropane and ammonia.
Answer
The skeletal formula of the main organic species formed can be represented as follows:
H H
\ /
N
/ \
C C
\ /
C
/
Br
The amine product is typically used as a hair conditioner or surfactant.