Which of the following is a non-electrolyte?

Which of the following aqueous solutions having same molality exhibits maximum boiling point elevation? (Assume complete dissociation)

If sodium sulphate is considered to be completely dissociated into cations and anions in aqueous solution,the change in freezing point of water $(\Delta T_f),$ when $0.01 \ mol$ of sodium sulphate is dissolved in $1 \ kg$ of water,is $(K_f = 1.86 \ K \ kg \ mol^{-1})$ (in $K$).

Which of the following is not a non-electrolyte?

Assuming $100\%$ dissociation of $1 \ m$ $KCl$ solution in water,the freezing point of the solution will be ........ $^oC$. $(K_f = 1.86 \ K \ kg \ mol^{-1})$

Calculate the depression in the freezing point of a solution containing $0.1 \ g$ of $K_3[Fe(CN)_6]$ in $100 \ g$ of $H_2O$. (Molecular weight of $K_3[Fe(CN)_6] = 329 \ g \ mol^{-1}$; $K_f = 1.86 \ K \ kg \ mol^{-1}$)