1. Which of the following compounds give a positive bromine test (disappearance
ID: 792145 • Letter: 1
Question
1. Which of the following compounds give a positive bromine test (disappearance of red)? a. pentane b. 1-petene c. hexane d. 2-hexene
2. A student prepares cyclohexene from cyclohexanol, but forgets to do the extractions. As a result the product contains some cyclohexanol. What peaks would you expect to see in the IR spectrum of this impure product?3. A centrifuge tube contains 4-methylcyclohene and an aqueous sodium chloride solution. Why are two distinct layers formed? Which layer contains 4-methylcyclohexene, why?
4. In this experiment, phosphoric acid was used as a catalyst. What is the purpose of a catalyst? 2. A student prepares cyclohexene from cyclohexanol, but forgets to do the extractions. As a result the product contains some cyclohexanol. What peaks would you expect to see in the IR spectrum of this impure product?
3. A centrifuge tube contains 4-methylcyclohene and an aqueous sodium chloride solution. Why are two distinct layers formed? Which layer contains 4-methylcyclohexene, why?
4. In this experiment, phosphoric acid was used as a catalyst. What is the purpose of a catalyst?
Explanation / Answer
1) b, d
2) in IR spectram 3400 -3500 broad peak for OH group in cyclohexanol, and 3000-3100 for C-H streatching incyclohexane
3) upper layer should contains 4-methyl cyclohexane, because its density is lower compare to aqueous sodium chloride solution
4) phosphoric acid is acid catalyst, it used for dehydration of alcholos to alkenes