Question

Which statement or set of conditions listed below is not consistent with an Syl reaction pathway? a. The leaving group is typically the conjugate base of a strong acid. b. The temperature is relatively "cooler" to reduce competing elimination products. c. The solvent is polar and protic. d. All of these are consistent with an Sni pathway. e. Neutral nucleophile work just fine. f. The rate is not dependent upon the concentration of the nucleophile. · The substrate has a leaving group that is typically on a methyl, 1° or 2° carbon.

Answer 1

Solution:

Inconsistent options

Option f is not consistent with SN1 reaction.

Rate of SN1 reaction is not dependent on the concentration of nucleophile but it is dependent on substrate concentration.

Option g is also not consistent with SN1 reaction.

Substrate used in SN1 reaction is typically has Tertiary carbon, For SN2 reaction substrate has methyl, primary or secondary carbon.

Option d is not consistent,

Since two options are found to be not consistent

Consistent Options

Option a: Leaving group is generally Br, Cl, OTf etc, these are conjugate bases of acids such as HBr. HCl, HOTf etc.

Option b: Usually cooling is required to keep tertiary carbocation for longer time that will avoid elimination reaction.

Option c : In polar protic solvent this reaction run smoothly

Option e : Since, a leaving group departs in the SN1 reaction leaving behind reactive tertiary carbocation thus neutral nucleophile can reacts with this carbocation.