Question

Which of the following is not Lewis acid ?

• A. $AlCl_3.6H_2O$
• B. $AlCl_3$
• C. $SnCl_4$
• D. $FeCl_3$

Answer 1

Answer: (A)

$AlCl_3.6H_2O$

Answer 2

$AlCl_{3}$, $SnCl_{4}$ and $FeCl_{3}$ act as Lewis acids because central atom in them have one vacant $3p$ orbital and five $3d$ orbitals. But in $AlCl_{3}$ $6H_{2}O$, all these empty orbitals get occupied. Hence it cannot act as Lewis acid