What osmotic pressure , p , could be produced inside a red blood cell if the red blood cell was immersed in pure distilled water and it did not burst. The concentration of the contents inside a red blood cell is approximately 0.30 M at 25 ° C.

Question

Quizplus · Accepted Answer

The osmotic pressure (p) can be calculated using the following formula: 
p = MRT, 
where M is the molar concentration of the solute (0.30 M), R is the gas constant (0.0821 L·atm/mol·K), and T is the temperature in Kelvin (25 °C = 298 K).

When the red blood cell is immersed in pure distilled water, the concentration of solute outside the cell is 0 M. Thus, the pressure inside the cell will increase until an equilibrium is reached where the osmotic pressure inside the cell is equal to the hydrostatic pressure outside the cell. Since the red blood cell does not burst, this means that the osmotic pressure inside the cell is less than or equal to the hydrostatic pressure outside the cell.

Assuming that the hydrostatic pressure outside the cell is 1 atm, we can calculate the osmotic pressure inside the cell:
p = (0.30 M) (0.0821 L·atm/mol·K) (298 K) = 7.34 atm

Therefore, the best choice is B, with an explanation as to how the answer was obtained.

What Osmotic Pressure , P , Could Be Produced Inside