Question

17.4% (w/v) K2SO4 (Mw = 174 g/mol) solution at 27°C is isotonic to 4% (w/v) NaOH solution at same temperature. If NaOH is 100% ionized, what is % ionization of K2SO4 in aqueous solution

Answer 1

Isotonic solutions have same osmotic pressure. Osmotic pressure (p) =icRTSince solutions are isotonic,(ic)NaCl = (ic)K2SO4For NaCl, i=2, since it dissociates 100%.c for NaCl = 5.85c for K2SO4 = 17.84Sunstiuting the values we get i= 0.655i.e K2SO4 is 65.5% ionised