Equimolar solution of the following substances were prepared separately. Which one of these will record the highest pH value?

Options

A. `SrCl_2`
B. `BaCl_2`
C. `MgCl_2`
D. `CaCl_2`

Answer

B

Explanation

All salts are soluble in water and give strong acid and weak base
`SrCl_2+2H_2O to Sr(OH)_2+ 2HCl`
`BaCl_2 + 2H_2O to Ba(OH)_2 + 2HCl`
`MgCl_2 + 2H_2O to Mg(OH)_2+2HCl`
`CaCl_2 + 2H_2O to Ca(OH)_2 +2HCl`
The basic nature of alkaline earth metals generally increases from Be to Ra. Thus, the order of basic nature of these hydroxides is
`Mg(OH)_2 lt Ca(OH)_2 lt Sr(OH)_2 lt Ba(OH)_2`
hence, pH is highest for `BaCl_2` .(As pH increases with basic nature)