Answer to Question #134908 in General Chemistry for Nielle

Question

Why do some compounds precipitate and some do not? express in terms of attraction to water and attraction to other ions.

Answer 1

A compound will precipitate from its aqueous solution when the counter iones (cations and anions ) has very poor interaction with water.

If these counter iones of a salt get more stability in (cation + anion) Ione pair rather than water solvated cation (cations sarrounded by water) or water solvated anion (anion sarrounded by water). Then a tinny amount of salt get dissolved in water. Then addition of any counter iones of this compound into the solution leads to the compound to get precipitate.

Where as, when counter iones of a salt get more stability as water solvated cation (cations sarrounded by water) or water solvated anion (anion sarrounded by water) form rather than in (cation + anion) Ione pair, due to the good interaction between water and counter iones of the salt then the compound unable to form precipitate on addition any counter ione of that compound into the solution of it.