Provide examples of osmotic pressure in daily life.

At $0^{\circ} C$,a urea solution has an osmotic pressure of $400 \ mm$. On dilution by $x$ times,its osmotic pressure decreases to $100 \ mm$ at $20^{\circ} C$. The dilution factor $x$ is approximately

$A$ 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 ideal method to determine osmotic pressure is ...... .

Find the amount of solute in a solution obtained by dissolving it in $2.5 \ dm^3$ of water that generates an osmotic pressure of $0.245 \ atm$ at $300 \ K$. (Molar mass of solute $= 58 \ g \ mol^{-1}$,$R = 0.0821 \ dm^3 \ atm \ K^{-1} \ mol^{-1}$) (in $g$)

Which of the following pairs of solutions can be isotonic at the same temperature?