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Which statement is correct about the molecule shown? A - AQA - A-Level Chemistry - Question 10 - 2018 - Paper 3
Question 10
Which statement is correct about the molecule shown? A. It reacts with HBr in an electrophilic substitution reaction. B. It reacts with NaBH4, in a nucleophilic ad... show full transcript
Worked Solution & Example Answer:Which statement is correct about the molecule shown? A - AQA - A-Level Chemistry - Question 10 - 2018 - Paper 3
Step 1
A. It reacts with HBr in an electrophilic substitution reaction.
Answer
This statement is incorrect. Electrophilic substitution reactions typically occur with aromatic compounds where a hydrogen atom is replaced by another substituent. The presence of a bromine substituent can activate the ring towards electrophilic substitution; however, HBr at moderate conditions does not typically participate in substitution reactions with this molecule.
Step 2
B. It reacts with NaBH4, in a nucleophilic addition-elimination reaction.
Answer
This statement is also incorrect. NaBH4 is a reducing agent that typically reduces carbonyl compounds. It does not participate in nucleophilic addition-elimination reactions with this molecule as it's not characterized by a carbonyl group or suitable electrophilic site for this reaction.
Step 3
Step 4
D. It reacts with KCN in a nucleophilic substitution reaction.
Answer
This statement is correct. The presence of bromine (a good leaving group) allows KCN to perform nucleophilic substitution. The cyanide ion (CN⁻) can attack the carbon bonded to the bromine, resulting in the substitution product.