Question

Which of these is not a nucleophile? How can you tell?

`H_2O`
`CH_3O^-`
`NH_3`
`NH_4^+`

Answer 1

For the following choices, the one which cannot served as a nucleophile will be last one, the ammonium ion.

Explanation:

Generally, for a species/compound to act as nucleophile, an easy way to determine it is to look for the presence of lone pairs on its Lewis structure.