The aqueous solution of potash alum is acidic due to hydrolysis of

Options

A. `K^(+)`
B. `Al^(3+)`
C. `SO_(4)^(--)`
D. presence of acid in its crystal as impurity

Answer

B

Explanation

`Al^(3+)` having high charge density will associate strongly with water through its fractional negatively charged oxygen pole and in such interaction there will be hydrolysis to some extent:
`Al^(3+)+H_(2)OhArr[Al(OH)^(2+)] + H^(+)`
The product cation may hydrolyse further.