Osmotic pressure

Question

0.85% aqueous solution of NaNO3 is apparently 90% dissociated at 27°C. Calculate the osmotic pressure of the solution.

Answer 1

The molar mass of sodium nitrate is 85 g/mol.

The degree of dissociation, α = 0.9 

The vant Hoff's factor, i = [ 1 + ( n ′ − 1 ) α ] = [ 1 + ( 2 − 1 ) 0.9 ] = 1.9 

The osmotic pressure, Π = iCRT = 1.9 × 0.1 × 0.08206 × 300 = 4.64 atm