Classify #BX_3#, #"water"#, #"ammonia"#, #"alcohols"#, as electrophiles or nucleophiles?

1 Answer
Jan 18, 2017

Answer:

#"Boron trichloride is an electrophile..........."#

Explanation:

Ammonia, water, and alcohols, are all potential nucleophiles due to the lone pair(s) of electrons on the nitrogen or oxygen atoms.

On the other hand, the boron centre in #BCl_3# is sextet rather than octet, and as a result boron trichloride is a potent electrophile, i.e. it accepts electron density.

Much of the chemistry of #BX_3# may be rationalized by this Lewis acidity; the propensity of boron to react with a donor atom to form #""^(-)BX_3X'^# species.