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Equimolar solutions of the following substances were prepared separately. Which one of these will record the highest pH value?
A
$BeCl_2$
B
$BaCl_2$
C
$AlCl_3$
D
LiCl
Detailed Solution
$BaCl_2$ is a salt of a strong acid (HCl) and a strong base ($Ba(OH)_2$). It does not hydrolyse, so its solution is neutral (pH = 7).
$BeCl_2$ and $AlCl_3$ are salts of weak bases; their small, highly charged cations hydrolyse and make the solution acidic (pH < 7).
$Li^+$ is also small and slightly hydrolysed, so LiCl solution is very slightly acidic.
So $BaCl_2$ records the highest pH.
$BeCl_2$ and $AlCl_3$ are salts of weak bases; their small, highly charged cations hydrolyse and make the solution acidic (pH < 7).
$Li^+$ is also small and slightly hydrolysed, so LiCl solution is very slightly acidic.
So $BaCl_2$ records the highest pH.