What are electron-deficient compounds? Are `BCl_(3)` and `SiCl_(4)` electron-deficient species? Explain.

Explanation

Electron deficient compounds are the compounds in which the central atom in their molecules has urge or tendency to take up one or more electron pairs. The electron deficient compounds are also called Lewis acids.
Yes, both `BCl_(3)` and `SiCl_(4)` are electron deficeint. Whereas B atom has a vacant 2p orbital, Si atom at the same time has vacant 3d-orbitals. both these atoms can take up electron pairs from electron donor species.