Question

If the human eye has an osmotic pressure of 8.00 atm at $\mathbf{25}\mathbf{°}\mathbf{C}$, what concentration of solute particles in water will provide an isotonic eyedrop solution (a solution with equal osmotic pressure)?

Short answer

The occurrence of solvent passing through a semipermeable membrane creates osmotic pressure. The concentration of water that will be needed for an isotopic eyedrop solution is 0.32 mol/L.

Step-by-step solution

Step 1:

It is given that:

Osmotic pressure ($\pi$) = 8.0 atm

Temperature (in kelvin) = $25\text{+273=298k}$

$\text{S=0.0821Latm/mol/k}$

Step 2:

The osmotic pressure for a solution is given by $\pi =\frac{\text{n}}{\text{V}}\text{ST}$, Here n is the number of moles and V is the volume of solution.

As the ratio of moles and volume gives the concentration of a compound, the above can be rewritten as:

$\begin{array}{l}\pi =\text{CST}\\ \\ \text{C=}\frac{8}{0.0821\times \text{298}}\text{=0.32mol/L}\end{array}$

Therefore, 0.32 mol/L of water will provide an isotonic eyedrop solution.