Question

12. Label the following reactions as El or E2 * 01 - 0 a . CH CH -- A. A =E1; B=E2 B.A=E1; B=E1 C. A E2: B-EI D. A=E2; B-E2 13. Consider the following exothermic E2 reaction. What rate equation would be observed for this reaction CH, CH CH I + KOC(CH3), CH CH CH2 + KI A. rate k[CHCH:CH-1) B. rate=k[CH,CH:CH:1][K OC(CH.)s] C. rate - [CH,CH:CH=1][K OC(CH);]* D. rate=k[CH,CH:CH-1)^[K OC(CH.):] E. There is not enough information given to determine the rate equation 14. When alkyl halides react, rearrangements are likely to occur in which of the following type(s) of reaction(s)? A. SI B. S2 C. El D. Both Sx2 and E2 E. Both Sul and El 15. Which of the following statements is (are) true about an El mechanism? A. The reaction is fastest with 3 alkyl halides. B. A better leaving group makes the reaction rate increase. C. The identity of the base affects the rate of reaction. D. Both (The reaction is fastest with 3° alkyl halides) and (A better leaving group makes the reaction rate increase) are true. E. Statements (The reaction is fastest with 3° alkyl halides), (A better leaving group makes the reaction rate increase), and (The identity of the base affects the rate of reaction) are all true.

Answer 1

12. The correct option is C. A = E2 and B = E1 since in Reaction A strong base tertiary butoxide is used which favors E2 elimination. In reaction B weak base methanol and tertiary alkyl bromide is present which favors E1 elimination reaction mechanism. 13. The correct option is B. Rate = k [CH3CH2CH2!] [K-OC(CH3)3] since in the given reaction follow E2 reaction mechanism, the rate depends on concentration of the reactant as well as the base used. 14. The correct option is E. Both SN1 and E1 since both SN1 and E1 reaction mechanisms proceed via carbocation intermediate, which tend to undergo rearrangement to form a stable carbocation intermediate. 15. The correct option is D This is because, the statement A is true, as tertiary halides are fastest in E1 reaction and as in statement B a better leaving group makes reaction rate increase. However, the identity of the base doesn't affect the E1 reaction rate, because the base concentration is not involved in the rate-determining step. Hence statement is not true.