Question

Place the following solutions in order of increasing osmotic pressure. 

I 10.15 M C2H602 

II. 0.15 M BaCl2 

III. 0.15 M Nal 

Answer 1

Since BaCl₂ and NaI are strong electrolytic compounds, hence in solution they are completely dissociate into ions. On the other hand, C₂H₆O₂ is a covalent or non-electrolytic compound and doesn't produce ions.

Now, BaCl₂ on dissociation produces three ions i.e. .

Hence, in 0.15 M BaCl₂ solution, the concentration of ions = 3 * 0.15 M = 0.45 M.

Similarly, on dissociation NaI produces 2 ions i.e. .

Hence, in 0.15 M NaI solution, the concentration of ions = 2 * 0.15 M = 0.30 M.

Now, osmotic pressure is a colligative property and it is directly proportional to the the number of particles (ions or molecules) present in a solution. Since the increasing order of concentration of ions or molecules is ​​​​​​Hence, the increasing order of osmotic pressure is or .