View Full Version : organic


pistolpete007
06-27-2008, 03:45 PM
Which of the following sets of hydrocarbons correctly displays free radicals in descending order of stability?

A.CH3H2C. > CH2=CHĊH2 > (CH3)3C. > (CH3)2HC.
B.CH2=CHĊH2 > (CH3)3C. > (CH3)2HC. > CH3H2C.
C.CH3H2C. > CH2=CHĊH2 > (CH3)3C. > (CH3)2HC.
D.(CH3)2HC. > CH3H2C. > CH2=CHĊH2 > (CH3)3C.
E.(CH3)3C. > CH2=CHĊH2 > (CH3)2HC. > CH3H2C.
is CH2CHCH2 the most stable bc it is vinylic and it wont even react with sn1 or sn2?

ALSO
Which of the following compounds will have its proton(s) shifted furthest and downfield on a 200 MHz 1H NMR spectrum?

A.CH3CH3
B.CH3CI3
C.CH3I
D.CH2I2
E.CHI3

IF B. was CHCl3 would that be the correct answer since Cl is more electrognegative than I?

mddang
06-27-2008, 03:55 PM
For the first question, in order of decreasing stability of radicals..

Allylic>tertiary>secondary>primary>methyl.


For the next problem, if CHCl3 were an answer choice, then yeah, it would be more downfield.

pistolpete007
06-27-2008, 04:15 PM
which is more stable allylic or vinylic

bergoshe
06-27-2008, 08:11 PM
which is more stable allylic or vinylic

allylic by resonance

dleodyddlek
06-27-2008, 08:59 PM
I believe, for second question,


"Which of the following compounds will have its proton(s) shifted furthest and downfield on a 200 MHz 1H NMR spectrum?

A.CH3CH3
B.CH3CI3
C.CH3I
D.CH2I2
E.CHI3

IF B. was CHCl3 would that be the correct answer since Cl is more electrognegative than I?"


B.CH3Cl3: it's not CH3(Cl)3 [which is not a possible structure] but CH3C(I)3
but yea if you compare CHCl3 to CHI3, CHCl3 will be shifted further.

pistolpete007
06-28-2008, 12:14 AM
ok so allylic more stable than teriarty


but teriary is more stable than vinylic right?