Among the colligative properties,which one is the best method for the determination of the molar mass of proteins and polymers?

Which of the following statements associated with an isotonic solution is not correct?

$A$ solution of a substance containing $1.05 \ g$ per $100 \ mL$ was found to be isotonic with $3 \% (w/v)$ glucose solution. The molecular mass of the substance is :

If the osmotic pressure of a solution at $300 \ K$ is $0.0821 \ atm$,what will be the concentration of the solution in $mol/L$?

At a certain temperature,the osmotic pressure of a $0.25 \, M$ solution of a non-electrolyte is $\pi \, bar$. What will be the osmotic pressure of a $0.125 \, M \, Ba(NO_3)_2$ solution at the same temperature?

If $3 \ g$ of glucose (molar mass $= 180 \ g \ mol^{-1}$) is dissolved in $60 \ g$ of water at $15^{\circ} C$,the osmotic pressure of the solution will be (in $atm$)