Question

The osmotic pressure of blood is 7.65 atm at ${37}^{\circ }C.$ How much glucose should be used per L for an intravenous injection that is to have the same osmotic pressure as blood?

• A. $27.1g$
• B. $44.6g$
• C. $54.0g$
• D. $89.2g$

Answer 1

The correct option is C $54.0g$

The osmotic pressure is given by $\Pi =CRT$
Here, $C$ is the molar concentration, $R$ is the ideal gas constant $(0.08206$ L atm / mol . K$)$ and $T$ is the absolute temperature.

Now,

$7.65=C\times 0.08206\times (273+37)$
$\therefore C=0.3M$

$\Rightarrow 1L$ of the solution will contain $0.3$ moles of glucose. The molar mass of glucose is $180$ g/mol.

This corresponds to $0.3\times 180=54.0g$ of glucose.