Carnallite in solution in $H_2O$,shows the properties of

If $0.004 \ M \ Na_2SO_4$ and $0.01 \ M$ glucose aqueous solutions are isotonic,then the degree of dissociation of $Na_2SO_4$ is ........ $\%$.

Which of the following aqueous solutions exhibits the minimum freezing point depression upon complete dissociation?

The van't Hoff factor $(i)$ for a dilute aqueous solution of the strong electrolyte barium hydroxide is

$0.8 \ mL$ of acetic acid of density $1.06 \ g \ mL^{-1}$ when dissolved in $1 \ kg$ of water causes a depression in freezing point by $0.0325^{\circ} C$. The Van't Hoff factor is:
$(K_{f} \text{ of } H_2O = 1.86 \ K \ kg \ mol^{-1})$

Which of the following is not a non-electrolyte?