Question

Among the following electron, deficient compound is

• A. ${\mathrm{CCl}}_4$
• B. ${\mathrm{PCl}}_5$
• C. ${\mathrm{BCl}}_3$
• D. ${\mathrm{SiF}}_4$

Answer 1

The correct option is C

${\mathrm{BCl}}_3$

Explanation for the correct option:

(c) ${\mathrm{BCl}}_3$

• In ${\mathrm{BCl}}_3$ , boron has $6$ valence electrons ($3$ boron and $3$ chlorine)
• Thus the octet configuration is two electrons short.
• Thus, ${\mathrm{BCl}}_3$ is an electron-deficient molecule.

Explanation for the incorrect options:

(a) ${\mathrm{CCl}}_4$

• In ${\mathrm{CCl}}_4$ , carbon has $8$ valence electrons ($4$ carbon and $4$ chlorine)
• Thus the octet configuration is full.
• Thus, ${\mathrm{CCl}}_4$ is an inert gas molecule.
• Hence this option is not correct.

(b) ${\mathrm{PCl}}_5$

• In ${\mathrm{PCl}}_5$ , phosphorus has $10$ valence electrons ($5$ phosphorus and $5$ chlorine)
• Thus the octet configuration is two electrons more.
• Thus, ${\mathrm{PCl}}_5$ is an expanded valence molecule.
• Hence this option is not correct.

(d) ${\mathrm{SiF}}_4$

• In ${\mathrm{SiF}}_4$ ,silicon has $8$ valence electrons ($4$ silicon and $4$ fluorine)
• Thus the octet configuration is full.
• Thus, ${\mathrm{SiF}}_4$ is an inert gas molecule.
• Hence this option is not correct.

Hence, the correct option is (C) i.e., ${\mathrm{BCl}}_3$.