JEE Main2014ChemistrySolutionsActual
Consider separate solutions of 0 . 500 M C 2 H 5 OH aq , 0 . 100 M Mg 3 PO 4 2 aq , 0 . 250 M KBr aq and 0 . 125 M Na 3 PO 4 aq at 25 ° C . Which statement is true about these solutions, assuming all salts to be strong electrolytes?
Options
- AThey all have the same osmotic pressure.
- B0 . 100   M   Mg 3 ( PO 4 ) 2   aq has the highest osmotic pressure.
- C0 . 125   M   Na 3 PO 4   aq has the highest osmotic pressure.
- D0 . 500   M   C 2 H 5 OH   aq has the highest osmotic pressure.
Correct answer
A. They all have the same osmotic pressure.
Step-by-step solution
Osmotic pressure π = iCRT (i is Van't Hoff factor, C is concentration) π = iC at same temperature. C 2 H 5 OH = 1 x 0 . 5 = 0 . 5 Mg 3 ( PO 4 ) 2 = 5 x 0 . 1 = 0 . 5 KBr = 2 x 0 . 25 = 0 . 5 Na 3 PO 4 = 4 x 0 . 125 = 0 . 5 The solutions are isotonic as they have the same osmotic pressure.