Question

of the two bromoderivators, C6H5CH (CH3)Br and C6H5CH(C6H5)Br, which one is more reactive in sn1 substitution reaction and why?

Answer 1

as Sn1 substitution reaction prefer carbonation
as in first compound due to an electron withdrawing group and releasing group hence less reactive
while in other compound due to
both releasing group carbonation nature increases
hence second compound undergo Sn1 more readily then first

Answer 2

Hii friend,

The nucleophilic reaction is also known as bimolecular reaction. This is because, the reaction occurs in a single step.

The condition for sn1 substitution reaction is,

(1) solvents should be polar
(2) carbonations should be strong
(3) It will be easily donating group.

OK now let's come to the point.

The reactivity series of sn1 mechanism is,

Benzyl > allyl > 3° >2° >1° > Ch3X

"This is the general concept. from this you can compare any groups".

by given,

The more reactive one is C6H5Br which is (Benzyl) than the Ch3Br which is (alkyl).

Hope this helps you a little!!!

If you have any further doubt please notify me!!!!