Answer
$B(OH)_3$ is a Lewis acid.
Work Step by Step
- $B$ has, naturally, 3 electrons, and it is making 3 covalent bonds with the oxygens: total of 6 electrons in its valence shell.
- Since this atom is from the second row of the periodic table, it is capable of holding 8 electrons in its valence shell.
- Therefore, it is capable of accepting 2 more electrons, making it a Lewis acid
