Question

Which of the following is a Lewis acid?
(For polyatomic species, consider the Lewis acid behaviour of the central atom).

a. ) NH3
b. ) F-
c. ) H2O
d. ) PF5
e. ) BF3

Answer 1

Don't know why the options didn't show.

they are
NH3
F-
H2O
PF5
BrF3

Answer 2

The others didn't show probably because you tried to copy and paste. That doesn't work. You must type what you want to post.
My recommendation:
Draw the Lewis electron dot structure for each of the molecules you list. Then look to see which of the central ions can accept electrons.

Answer 3

Thanks for the headsup.

Yeh I have drawn the Lewis structures. How do I know which ions can accept electrons? Does that mean it has a unpaired electron?