Question

Which one of the following salt is more acidic in water?

• A. $BeC{l}_2$
• B. $NiC{l}_2$
• C. $FeC{l}_3$
• D. $AlC{l}_3$

Answer 1

Answer: (D)

$AlC{l}_3$ on hydrolysis gives weak base $\left[Al\right(OH{)}_3]$ and strong acid $\left[HCl\right]$ among all.

All other compound also give strong acid $HCl$ and their corresponding weak salt such as $Ni{\left(OH\right)}_2$, $Be{\left(OH\right)}_2$ and $Fe{\left(OH\right)}_3$, but among them $Al{\left(OH\right)}_2$ is weakest base thus the solution of $AlC{l}_3$ is more acidic.

Hence option D is correct.