Consider the separate solution of `0.500MC_(2)H_(5)OH(aq.) 0.100 M Mg_(3)(PO_(4))_(2)(aq.),0.250MKBr(aq)and 0.125M Na_(3)PO_(4)(aq) at25^(@)C`.What is statement is true about these solutions,assuming all salts to be strong electrolytes?

Options

A. They all have same osmotic pressure
B. `0.100MMg_(3)(PO_(4))_(2)(aq)` has thehighest osmotic pressure.
C. `0.125MNa_(3)(PO_(4))_(2)(aq)`has the highest osmotic pressure
D. `0.5000 MC_(2)H_(5)OH(aq)` has the highest osmotic pressure.

Answer

A

Explanation

Osmotic pressure ,`pi=ixxMRT`
where ,i=van't Hoff factor ,M=Molarity R=gas constant ,T=Temperature
For`0.500MC_(2)H_(5)OH(aq).i=1`,thus,
`pi !=_(C_(2)H_(5)OH)(aq)=0.5RT`
for `0.100 M Mg_(3)(PO_(4))_(2)(aq),i=5`
`[because Mg_(3)(PO_(4))_(2)hArr 3Mg^(2+)+2PO_(4)^(3-)]`
Thus,`pi_(Mg_(3)(PO_(4))_(2))(aq)=5xx10.1xxRT`
For `0.125 MNa_(3)PO_(4)(aq),i=4`
`[because Na_(3)PO_(4)hArr 3Na^(+)+PO_(4)^(3-)]`
Thus, `pi_(na_(3)PO_(4))(aq)=4xx0.125xxRT=0.5RT`
Hence the solutions have same osmotic pressure.