If you know, in chemistry we have an empirical rule: polar substances are soluble in polar solvents and non-polar substances in non-polar solvents. In my lab we have tested two salts (KCl and NaCl) and calculated their solvation enthalpies in the water. May I ask you what's your prediction about these processes.
I predict that both substances will dissolve in water because both substances are partially ionic and polar and as water is very good solute as it is polar. But I think two latter substances are also more polar than ionic as the electronegativity is > 2.0 in both substances. Therefore, it is very likely the reaction will happen.
Furthermore, I predict that the temperature will increase in the water when NaCl is added into water and temperature will decrease when KCl is added into water.
Here, I do not know why the temperature will increase in the former dissolution and decrease in the latter dissolution.
I think this is because of Gibbs free energy.Thanks for your reply!