Hi UltimaOnline,
I've a few questions here to consult you.
Q1: IJC/09/P1/39
In which sequence are the compounds listed in order of
increasing ease of hydrolysis?
Choice 3 (chlorobenzene, chloromethane, chloroethane) is not a
correct choice.
Remarks: In ascertaining the ease of hydrolysis, I'll first have
to see the C-X bond strength. Since it's the same in this choice,
I'll have to consider either (I) Resonance within the reactant and
(II) stability of the intermediate products.
In this case, shouldn't 3 also be correct? What's the difference
in the electron donating effect between the methyl and ethyl
substituent?
Q2: In relation to VJC/09/P1/29:
Remarks: How do I establish the relative acidity of an alcohol
(CH3CH2OH) to that of an acidic salt (CH3CH2NH3+Cl-)?
Q3: VJC/09/P1/23
Remarks: It must have been my blind spot, but why is A not an
acceptable answer as well?
Thank you very much Ultima!
Hi Gohby, no prob.
Q1. The diff btwn Me and Et groups, is the stability (and hence
Ea required) of the intermediate (if SN1) or transition state (if
SN2). Et group is more strongly electron-donating by induction,
which can better stabilize the intermediate or transition
state.
Q2. Acidic salts (notice the adjective?) are always more acidic
than alcohol (which is considered neutral, and even less acidic
than neutral water).
Q3. A is the *only* acceptable answer.
