Question

Why do some combinations of ionic compounds form a precipitate while others do not

Answer 1

Whether or not such a reaction occurs can be determined by using the solubility rules for common ionic solids.

tell me if i'm wrong

Answer 2

This is because of the solubility of the reacting metal salts.

Step-by-step explanation:

The use of solubility of salts influences the formation of precipitates. Most precipitation reactions occur as a result of the replacement reactions or double placement reactions. A double replacement reaction occurs when two ionic reactants dissociate and bond with respective anion and cation of the other reactant. This is simply a switch over reaction.

A double replacement reaction occurs when a chemical reaction occurs and one of the products formed is insoluble.

Here is an example:

`PdSO_((aq)) + K_(2)S_((aq)) = PdS_((s)) +K_(2)SO_(4)_((aq))`

Both reactants are acqeous and the product is solid.