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. They all have the same osmotic pressure.
B. `0.100 M Mg_3(PO_4)(aq)` has the highest osmotic pressure.
C. `0.125 M Na_2 PO_4` (aq) has the highest osmotic pressure.
D. `0.500 M C_2H_5OH(aq)` has the highest osotic pressure.

Answer

A

Explanation

`pi = iCRT`
`""^piC_2H_5OH = 1 xx 0.500 xx R xxT = 0.5 RT`
`""^(pi)Mg_3 (PO_4)_2 = 5 xx 0.100 xx R xxT = 0.5 RT`
`""^(pi)KBr = 2xx0.250 xx R xx T = 0.5 RT`
`""^(pi)Na_3PO_4 = 4 xx 0.125 xx RT = 0.5 RT`
Since the osmotic pressure of all the given solutions is equal. Hence all are isotonic solution.