Osmotic pressure is calculated by multiplying the molarity, temperature and the universal gas constant. It is expressed as:
P = iMRT
Say the temperature for both solutions is 373.15 K.
P(NaCl) = 2 x 0.10 x 0.08206 x 373.15 = 3.06 atm
P(KBr) = 2 x 0.10 x 0.08206 x 373.15 = 3.06 atm
They will have the same osmotic pressure since they have the same concentration, dissociate into 2 ions and at the same temperature.
