When only a little quantity of HgCl2(s) is added to excess KI (aq) to obtain a clear soltion, which of the following is true for this solution? (no volume change on mixing)

Due to this addition a complex [HgI4]2− will get formed as follows Hg2++4I−⇒[HgI4]2−or Hg2++2Cl−+4I−⇌[HgI4]2−+2Cl−on adding we can see that 4I− ions are consumed but resultant number of particles are three. Hence boiling point gets decreased. freezing point gets increased.