Final answer:
Yellow, orange or red precipitates often result from the formation of insoluble compounds such as lead iodide and silver dichromate. White precipitates can be formed from reactions such as the formation of silver chloride from calcium chloride and silver nitrate. All these involve precipitation reactions creating insoluble solids from ionic substances in solution.
Step-by-step explanation:
Chemical reactions resulting in a yellow, orange, or red precipitate often involve the formation of an insoluble solid. An example of such a reaction is when a colorless solution of lead (II) nitrate reacts with potassium iodide, yielding a yellow precipitate of lead iodide. Similarly, mixing a colorless solution of silver nitrate with a yellow-orange solution of potassium dichromate produces a reddish precipitate of silver dichromate.
In both examples, the commonality is the formation of an insoluble compound by a precipitation reaction, which is when two solutions are mixed resulting in a solid precipitate.
Reactions resulting in a white precipitate include the mixing of calcium chloride with silver nitrate, forming a white precipitate of silver chloride. Another can be seen when sodium hydroxide reacts with iron(II) chloride to potentially form a white precipitate of iron(II) hydroxide, although iron(II) hydroxide often further reacts with oxygen to give a rusty-brown iron(III) hydroxide precipitate. These reactions are characterized by the formation of insoluble salts from ionic compounds in solution.