Answer
$BCl_3$ is a Lewis acid.
Work Step by Step
- In the Lewis structure of this molecule, there are 3 "Cl" atoms connected to the central "B" atom.
- Since "B" has, naturally, 3 electrons in its valence shell, and it is making 3 covalent bonds, there is a total of 6 electrons in its valence shell.
- "B" is from the second row of periodic table: Capacitiy of 8 electrons on the valence shell.
- Therefore, there is space for more 2 electrons, so $BCl_3$ can act as a Lewis acid, receiving these electrons from other compound.
