Consider separate solution of `0.500M C_(2)H_(5)OH(aq), 0.100M Mg_(3)(PO_(4))_(2)(aq), 0.250M KBr(aq)` and `0.125 M Na_(3)PO_(4)(aq)` at `25^(@)C`. Which statement is true about these solutions, assuming all salts to be strong electrolytes?

Options

A. 0.500 M `C_(2)H_(5) OH_("(aq)")` , has the highest osmotic pressure.
B. They all have the same osmotic pressure.
C. 0.100 M `Mg_(3)(PO_(4))_(2"(aq)")` has the highest osmotic pressure.
D. 0.125 M `Na_(3)PO_(4"(aq)")` has the highest osmotic pressure.

Answer

B

Explanation

Osmotic pressure ,
` pi = icRT`
`pi [C_(2)H_(5)OH[ = 1 xx 0.500 RT = 0.5RT`
` pi [Mg(PO_(4))_(2)] = 5 xx 0.100 RT = 0.5 RT`
`pi [K BR] = 2 xx 0.25 RT = 0.5 RT`
`pi [Na_(3)PO_(4)] = 4 xx 0.125 RT = 0.5 RT`
Therefore , all have some osmotic pressure.