ineedchemhelp
Labrat

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« on: June 26, 2008, 06:12:33 PM » |
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hey guys,
I have a good idea of what the answers, I just want to double check with others.
1. which of the following are not good leaving groups? - C2H5O-- Cl- ( i found that this is an ok LG) - I- ( a very good leaving group) - CH3CO2- ( This is also an ok leaving group) - All of the above. I tried finding out information about the 1st option, but I am stuck. It is either down to option of or option 5.
2. Which nucleophilic subs. reaction would be unlikely to occur? - HO- + CH3CH2-I------> CH3CH2-OH+I - I- + CH3CH2-H----> CH3CH2-I + H- - CH3S- + CH3-Br---------> CH3S-CH3 + Br- - all of the above would be unilkely to occur. I am stuck between the first 2 options, I is a good leaving group, but as far as H and OH put in the reactions I am confused on which to pick.
3. Regarding tert-butoxide as an E2 reaction, which statement is wrong. - this base is more effective that ethoxide ion, becuase it (Ko-t- Bu) is more basic of the two. - it is reactive in dimethyl sulfoxide that in tert-butyl alcohol. - it will produce the more stable alkene. - it favors E2 of Sn2 I think option 2 is wrong, but than again I think the third option is wrong as well.
4. To covert 2-bromobutane to 1-butene in the highest yeild. Which are the best reagents? - KOH/H20 -KOH/CH3OH -CH3ONa/CH3OH -CH3CH2ONa/CH3CH2OH -(CH3)3COK/(CH3)3COH I know the first option is wrong, I think it is the 2nd one that deals with methonal.
5. Which of the following statments is/ are true of Sn2 reaction of (R)-2-bromobutane w/ hydroxide ion? - Doubling the hydroxide ion concentration would double the rate of the reaction. ( assuming all other experimental conditions are unchanged.) - The major product would be (s)-2-butanol. - Doubling the concentration of (R)-2-bromobutane would double the rate of the reaction. (assuming all other experimental conditions are unchanged.) - All of the above. - Two of the above. I think the third option is incorrect.
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