Answer
$OH^-$ is a Lewis base.
Work Step by Step
- Drawing the Lewis structure for $OH^-$, we will see that, the oxygen has 3 lone pairs and a negative charge, therefore, it is capable of donating these electrons, making it a Lewis base.
To draw this structure:
- Count the total electrons: "O": 6, "H": 1, Negative charge: 1 = 8 electrons
- Draw an "O" and an "H".
- Make a bond between them (-2 electrons = 6)
- Hydrogen has 2 electrons, so it is full already.
- Put the other electrons in the oxygen. (-6 electrons = 0)
