Diffusion of solvent through a semipermeable membrane is called

$A$ solution containing $10 \ g$ per $dm^3$ of urea (molecular mass $= 60 \ g \ mol^{-1}$) is isotonic with a $5 \%$ solution of a non-volatile solute. The molecular mass of this non-volatile solute is ........ $g \ mol^{-1}$.

The osmotic pressure of a living cell is $12 \ atm$ at $300 \ K$. The strength of sodium chloride solution that is isotonic with the living cell at this temperature is $...... \ g \ L^{-1}$. (Nearest integer)
Given : $R = 0.08 \ L \ atm \ K^{-1} \ mol^{-1}$
Assume complete dissociation of $NaCl$
(Given : Molar mass of $Na$ and $Cl$ are $23$ and $35.5 \ g \ mol^{-1}$ respectively.)

Which of the following aqueous solutions are isotonic $(R = 0.082 \ atm \ K^{-1} mol^{-1})$?

What is the osmotic pressure of a solution of $1.7 \ g$ of $CaCl_2$ in $1.25 \ dm^3$ of water at $300 \ K$,if the van't Hoff factor and molar mass of $CaCl_2$ are $2.47$ and $111 \ g \ mol^{-1}$ respectively (in $atm$)? $[R=0.082 \ dm^3 \ atm \ mol^{-1} \ K^{-1}]$

Assuming the compounds to be completely dissociated in aqueous solution, identify the pair of the solutions that can be expected to be isotonic at the same temperature.