A compound X (C4H9Br) undergoes the following reactions: C4H9Br NaOH(aq)/heat > C4H10O Cr2O7(2-), H+(aq)/ heat> C4H8O. What is X?
Correct answer: B. 2 - Bromobutane
- A. 1 - Bromobutane
- B. 2 - Bromobutane
- C. 1-Bromo-2-Methylpropane
- D. 2 - Bromo - 2 - Methylpropane
Explanation
C4H8O having one oxygen rules out the possibility of the intermediate compound being a primary alcohol as if it were to be a primary alcohol, a carboxylic acid would have been formed having 2 oxygen atoms in the molecule and not one. Thus, we can infer that the intermediate alcohol is a secondary alcohol and C4H8O is a ketone leading us to conclude that Bromine must have been on either carbon 2 or 3. Also, we must not have a side chain as it would either give us a tertiary alcohol with 10 hydrogens which wouldn't had oxidized further or a primary alcohol which would have oxidized to give a carboxylic acid. Both are not required so, based on the options provided we can choose B as the answer since it has no side chain and the bromine is not on the end carbons.
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About Alkyl Halides
Alkyl halides are named and related to their carbon-halogen structure, polarity and reactivity. The key reactions are nucleophilic substitution by SN1 and SN2 mechanisms and elimination by E1 and E2 mechanisms, including how substrate structure, nucleophile, base, solvent and temperature influence substitution versus elimination.
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