Which of the following substances shows the highest colligative properties?

The observed osmotic pressure for a $0.10 \ M$ solution of $Fe(NH_4)_2(SO_4)_2$ at $25 \ ^oC$ is $10.8 \ atm$. The expected and experimental (observed) values of van't Hoff factor $(i)$ will be respectively: $(R = 0.082 \ L \ atm \ K^{-1} \ mol^{-1})$

Which one has the highest boiling point?

Calculate the molality of an aqueous solution of an electrolyte that freezes at $-0.93 \text{ }^\circ\text{C}$. Given that $K_f$ for water is $1.86 \text{ K kg mol}^{-1}$ and the van't Hoff factor $(i)$ is $1.25$. (Freezing point of pure water $= 0 \text{ }^\circ\text{C}$) (in $\text{ m}$)

The molal elevation constant of water is $0.51 \ K \, kg \, mol^{-1}$. The boiling point of $0.1 \ m$ aqueous $NaCl$ solution is nearly .......... $^oC$.

Solutions $A$,$B$,$C$ and $D$ are respectively $0.1 \ M$ glucose,$0.05 \ M \ NaCl$,$0.05 \ M \ BaCl_{2}$ and $0.1 \ M \ AlCl_{3}$. Which one of the following pairs is isotonic?