The Van't Hoff factor for sodium phosphate would be

Which of the following salts has the same value of Van't Hoff factor $i$ as that of $K_4[Fe(CN)_6]$?

Which of the following will have the lowest vapor pressure?

The osmotic pressure of a $0.1 \ M$ solution of $NaCl$ and $Na_2SO_4$ will be:

For the dissociation of $Na_2SO_4$,how is the degree of dissociation $\alpha$ used to calculate the van't Hoff factor $(i)$?

Which one of the following electrolytes has the same value of van't Hoff factor $(i)$ as that of $Al_2(SO_4)_3$ (if all are $100 \%$ ionised)?