12. Which of the following is an incorrect statement about A) FeBr3 functions to

Question

12. Which of the following is an incorrect statement about A) FeBr3 functions to increase the electrophilicity of Br B)Formation of the the bromination of benzene by Br2 2. sigma complex is the rate-determining step of the mechanism. intermediate is resonance stabilized. C) The carbanionic D) There are two carbon-containing intermediates in the mechan E) The final step of the mechanism is loss of H+ ism. 13. When a carbonyl is part of a conjugated ?-network, the C-O stretch: A) has a higher frequency than in a nonconjugated system. B) has a lower frequency than in a nonconjugated system. always occurs at 1710 cm-1. occurs around 2700 cm-1, cannot be distinguished from the C-o stretch in a nonconjugated system. tocurbon NMR, the carbon atom of the carbonyl group in aldehydes and ketones has a chemical shift about A) 20 ppm. B) 40 ppm. C) 60 ppm. D) 120 ppm. E)200 ppm 15. The reagent which converts a carbonyl group of a ketone into a -CH2- group is: A) Na, NH3, CH CH2OH LiAlH4 C) NaBH4. CH3CH2OH D) Zn(Hg). conc. HC E) LiAIHIOC(CH3)s]s 16. The positively polarized carbon atom of a carbonyl group acts as: A) an electrophile and a Lewis base. B)a nucleophile and a Lewis base. ) an electrophile and a Lewis acid D) a nucleophile and a Lewis acid. E) both a Lewis acid and a Lewis base 17. Oxidation of a 1° alcohol with chromic acid results in the production of A) an ester B) a ketone an aldehyde an ether E) none of the above 18. In which compound does the carbonyl group absorb at the lowest frequency in the Infrare

Explanation / Answer

12. answer is option D

EXplanation

only one carbon containing intermediate is present in the mechanism

13. answer is option B. Has lower frequency than in a nonconjugated system

Explanation: due to conjugation bond order will be reduced therefore frequeny will be lower

14. Answer is option E.

Explanation: the carbonyl carbon is highly desheilded due to attached oxygen

15. Answer is option D.

Explanation: ketone can be converted to alkane by treatment with zinc amalgum and HCl it is clemmenson reduction

16. Answer is option C. an electrophilie and lewis acid

17. Answer is option E: none of the above

Explanation: treament of alcohol with chromic acid will give carboxylic acid.

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.