Isotonic solutions are solutions having the same

What is the effect of external pressure on the osmotic pressure $(OP)$ of a solution?

$A$ $5 \%$ solution of cane sugar (mol. wt. $= 342$) is isotonic with $1 \%$ solution of a substance $X$. The molecular weight of $X$ is

What is the osmotic pressure of a semi-molar solution at $27^{\circ} C$ (in $atm$)?
$(R = 0.082 \ L \ atm \ K^{-1} \ mol^{-1})$

$A$ solution of polystyrene in benzene contains $10 \, g/L$. The equilibrium height of the column of solution having density $0.9 \, g/mL$ in the osmometer is $11 \, cm$ at $27 \, ^\circ C$. What is the average molar mass of polystyrene? (Assume the solution is ideal)

The osmotic pressure of $2.22\ \%\ (w/v)$ $CaCl_2$ solution at $27\ ^oC$ is $(R = 0.08\ L\ atm\ K^{-1}\ mol^{-1})$