Which of the following is a non-electrolyte?

Which of the following is a non-electrolyte?

Which of the following solutions will show the maximum depression in freezing point when the concentration is $0.1 \, M$?

$A$ $0.5 \ m$ aqueous solution of a weak acid $(HX)$ is $20\%$ ionized. If $K_f$ for water is $1.86 \ K \ kg \ mol^{-1}$,the depression in freezing point of the solution is ....... $K$.

If $1$ mole of a solute dissociates to give $n$ number of ions,then the degree of dissociation $\alpha$ in terms of the van't Hoff factor $i$ is given by:

If a centimolal aqueous solution of $K_{3}[Fe(CN)_{6}]$ has a degree of dissociation of $0.78$,what is the value of the van't Hoff factor?