Question

Based on periodic trends, which would be a better nucleophile in Sn2 reactions, NH3 or H2O?



a. H2O

b. neither NH3 nor H2O can act as nucleophiles

c. both would be equally effective

d. NH3

Answer 1

Question#12067

Based on periodic trends, which would be a better nucleophile in Sn2 reactions, NH3 or H2O?

a. H2O

b. neither NH3 nor H2O can act as nucleophiles

c. both would be equally effective

d. NH3

Answer:

Nucleophile means "nucleus loving" which describes the tendency of an electron rich species to be attracted to the positive nuclear charge of an electron poor species, the electrophile.

Here is a table of relative nucleophilicities

Very Good I⁻, HS⁻, RS⁻

Good Br⁻, HO⁻, RO⁻, NC⁻, N3⁻

Fair NH3, Cl⁻, F⁻, RCO2⁻

Weak H2O, ROH

Very Weak RCO2H

That's why:

d. NH3