What is the expected value of $\Delta T_f$ for $1.25 \ m$ $CaCl_2$ solution if $1.25 \ m$ sucrose solution has $\Delta T_f$ value $x \ K$?

What is the freezing point (in $^\circ C$) of a solution containing $0.1 \ g$ of $K_3[Fe(CN)_6]$ (molar mass = $329 \ g \ mol^{-1}$) in $100 \ g$ of water? (Given $K_f = 1.86 \ K \ kg \ mol^{-1}$)

Consider the following solutions:
$I$. $1 \ M$ glucose $(aq.)$
$II$. $1 \ M$ sodium chloride $(aq.)$
$III$. $1 \ M$ acetic acid in benzene
$IV$. $1 \ M$ ammonium phosphate $(aq.)$

$17.4\% (W/V)$ of potassium sulphate $(mol. wt. = 174)$ is isotonic with $4\% (W/V)$ aqueous solution of $NaOH$. If $NaOH$ is $100\%$ ionised,the degree of ionisation of potassium sulphate is $.......... \%$.

The addition of a polar solvent to a solid electrolyte results in

$5 \ g$ of $Na_2SO_4$ was dissolved in $x \ g$ of $H_2O$. The change in freezing point was found to be $3.82 \ ^oC$. If $Na_2SO_4$ is $81.5 \%$ ionised,the value of $x$ ($K_f$ for water $= 1.86 \ ^oC \ kg \ mol^{-1}$) is approximately .............. $g$ (molar mass of $S = 32 \ g \ mol^{-1}$ and that of $Na = 23 \ g \ mol^{-1}$)