Non-existence of the linear relation between TH (homogeneous nucleation temperature) and Tm (melting temperature) for aqueous H2SO4 solution

Test of the linear relation between TH (homogeneous ice nucleation temperature) and Tm (melting temperature) was carried out for aqueous HCl and H2SO4 solutions. It is shown that the linear relation does not hold for aqueous H2SO4 solution. Enhancement of the ionization of sulfuric acid with decreasing temperature is the most likely cause for the curved relation between TH and Tm. In addition, close examination of the TH and Tm data for aqueous HCl solution indicates that the TH versus Tm relation for aqueous HCl solution seems very weakly curved.