Question

Which of the following halides is the most acidic ?

• A. $PCl_3$
• B. $SbCl_3$
• C. $BiCl_3$
• D. $CCl_4$

Answer 1

Answer: (A)

$PCl_3$

Answer 2

$CCI_4$ cannot accept a lone pair of electron. As such it is not a Lewis acid. Acid strength of trichlorides is in the order $PCl_3 > AsCl_3 > SbCl_3$ Thus $PCl_3$ is more acidic than $SbCl_3$