0.85% aqueous solution of `NaNO_(3)` is apparently 90% dissociated . The osmotic pressure of solution at 300 K is

Options

A. 4.674 atm
B. 46.74 atm
C. 2.46 atm
D. 4.674 mm Hg

Answer

A

Explanation

Molality, `C=(0.85xx1000)/(100 xx 85)=0.1 "mol L"^(-1)`
`{:(NaNO_(3),rarr,Na^(+),+,NO_(3^(-))),(1-alpha,,alpha,,alpha):}`
`i=(1-alpha+alpha+alpha)/(1)=1+alpha=1+0.90=1.90`
`pi=i"CRT" = 1.90xx0.1xx0.082xx300`
`=4.674` atm