Chemistry - Liquid Solution Question with Solution | TestHub

Osmotic pressure is given by $\pi =iCRT$.

For $0.1$ M NaCl solution, assuming complete dissociation, $i=2$.

${\pi }_{NaCl}=2\times 0.1\times RT=0.2RT$

For an isotonic glucose solution, the osmotic pressure must be equal to $0.2RT$. Since glucose does not dissociate, $i=1$.

${\pi }_{glucose}=1\times C\times RT=0.2RT$

$C=0.2$ M

Checking the given options for the concentration of glucose:

For the solution containing $18$ g glucose in $500$ ml solution:

Moles of glucose = $\frac{18}{180}=0.1$ mol

Volume of solution = $500$ ml = $0.5$ L

Molarity $C=\frac{0.1}{0.5}=0.2$ M

This matches the required concentration.

Answer: A solution containing $18$ g glucose in $500$ ml solution.