Which of the following conditions is correct for reverse osmosis? [$C =$ Concentration of solution in $mol \ L^{-1}$; $T =$ Temperature in Kelvin scale; $P_{ext} =$ External pressure; $\pi = CRT =$ Osmotic pressure]

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 $g$)

The solution containing $4.0 \ g$ of a polyvinyl chloride polymer in $1 \ L$ of dioxane was found to have an osmotic pressure of $6.0 \times 10^{-4} \ atm$ at $300 \ K$. Given $R = 0.082 \ L \ atm \ mol^{-1} \ K^{-1}$,the molecular mass of the polymer is:

$A$ 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 ........ $g \ mol^{-1}$.

$A$ solution is prepared by dissolving $0.6 \ g$ of urea (molar mass $= 60 \ g \ mol^{-1}$) and $1.8 \ g$ of glucose (molar mass $= 180 \ g \ mol^{-1}$) in $100 \ mL$ of water at $27 \ ^oC$. The osmotic pressure of the solution is : ............. $atm$ $(R = 0.08206 \ L \ atm \ K^{-1} \ mol^{-1})$