Is the sign of S what you would expect for a solid dissolving in water and breaking into ions? Solution if any solid is dissolved in water breaks into its respective ions means the no of ions in the products side increases. That means they will have short range interactions and moves randomly than their respective undissociated molecule. The main thing that we have to understand is that the randomness of ions more than the reactant. so S will be +ve for that process of dissolving a solid in water which breaks into its ions. Because Sreaction = Sproducts - Sreactants Thus, S = +ve. General example is NaCl + H2O -------> Na+ (aq) + Cl- (aq) Thanks..