71answer says 1/2
If the reaction of a mixture of NaCN and benzyl bromide were run in twice the volume of the solvent, the rate of reaction would nearly be :
a) same
b) twice as fast
c) 1/2 as fast
d) can't say as the nature of reaction is unknown.
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10 Answers
1i think it should be 1/4th. since SN2 is bimolecular rate depends on conc. of both.
so if volume is doubled =>conc. is halved => 1/2 * 1/2 = 1/4 * initial rate..
1sorry!! i didn't see benzyl bromide i took it as phenyl bromide.
then obviously it'll be 1/2 since it is SN1 reaction.
:)
71I'm sure you won't bid so strongly for a SN1 reaction just because it's a 1 degree benzyl carbocation without knowing about the kind of solvent and Nucleophile?
1i think it will favours sn2 mechanism , since the carbocation formed is 1° and also Br is better leaving group than CN and rest depend on solvent being protic or aprotic ....
71So. I guess the question is set without thinking hard.
1No, It will be SN1 only. The carbocation will undergo resonance. Also Benzyl halide is preferred for SN1 than SN2. Given in Jagdamba, if you refer that
71The CORRECT answer is not in the options. it'll be SN2, and 1/4 as fast.
71See here: Written very clearly
http://www.jce.divched.org/jcedlib/qbank/collection/conceptests/rxnnucle.html