Which of the following is not a non-electrolyte?

$A$ $0.1 \ m$ aqueous solution of a weak acid $HX$ is $30\%$ ionized. If $K_f$ for water is $1.86 \ ^{\circ}C/m,$ the freezing point of the solution will be ......... $^{\circ}C$.

What will be the osmotic pressure in $atm$ of a $0.2 \ M$ $K_4[Fe(CN)_6]$ solution at $27 \ ^oC$?

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 $\text{ m}$)

At a certain temperature,the vapour pressure of pure water is $76 \ mm$ of $Hg$. When $1 \ mol$ of $Na_2SO_4$ is dissolved in $36 \ mL$ of water,the vapour pressure of the solution becomes $38 \ mm$ of $Hg$. What is the percentage dissociation of $Na_2SO_4$ in the solution?

In an aqueous solution of potassium ferrocyanide,the degree of dissociation of the salt is $80\%$. The value of the van't Hoff factor is: