The following statements are based on the osmotic pressure of solutions. The correct statements are.........

(A) Molar concentration is same for isotonic solutions
(B) Solutions which have same osmotic pressure at same temperature are called isotonic solutions
(C) No osmosis occurs when isotonic solutions are separated by semi-permeable membrane
(D) A 1.9 % Sodium Chloride solution has equivalent osmotic pressure to that of fluid inside blood cells

Choose the correct answer from the options given below:

(B) and (C) only

The correct answer is Option (4) → (B) and (C) only

(A) Molar concentration is same for isotonic solutions: Incorrect. While this is true for non-electrolytes (like sugar and urea), it is not a universal rule. Osmotic pressure ($\Pi$) depends on the total number of particles (the van 't Hoff factor, $i$). For example, a $0.1\text{ M}$ solution of $NaCl$ ($i=2$) is not isotonic with a $0.1\text{ M}$ solution of Glucose ($i=1$) because the $NaCl$ solution has twice the number of particles and thus higher osmotic pressure.

(B) Solutions which have same osmotic pressure at same temperature are called isotonic solutions: Correct. This is the fundamental definition of isotonicity. If two solutions exert the same osmotic pressure ($\Pi_1 = \Pi_2$) at the same temperature, they are isotonic.

(C) No osmosis occurs when isotonic solutions are separated by semi-permeable membrane: Correct. Since the osmotic pressures on both sides of the membrane are equal, there is no driving force for the net movement of solvent. While molecules move back and forth at a molecular level, the net osmosis is zero.

(D) A 1.9 % Sodium Chloride solution has equivalent osmotic pressure to that of fluid inside blood cells: Incorrect. Human blood cells are isotonic with a 0.9% (mass/volume) sodium chloride solution, commonly known as normal saline. A $1.9\%$ solution would be hypertonic, causing blood cells to lose water and shrink (crenation).