Which of the following are Lewis acids?

Options

A. `PH_3 and SiCl_4`
B. `BCl_3 and AlCl_3`
C. `PH_3 and BCl_3`
D. `AlCl_3 and SiCl_4`

Answer

B, D

Explanation

(b) `BCl_3 and AlCl_3` both have incomplete octate and act as Lewis acid.
(d) In `SiCl_4` , Si has vacant d-orbitals, thus it can accept a pair of electrons and act as a Lewis acid.