Question

Is `"F"^(-)` a Lewis acid?

Answer 1

No it's a base

Explanation:

So for a compound to be a lewis acid it has to be able to accept a lone pair of electrons (electron-pair acceptor) for instance `H^+` and `NH_4^+`. So these compounds are able to release a proton `(H^+)` as a Bronsted-Lowry acid.

A lewis base is a substance that can donate a lone pair of electrons (electron-pair donor). For instance `OH^-` and `F^-`.