Question

A student mixes a solution of lead (II) nitrate with a solution of potassium iodide and notices the formation of a yellow solid. What is the precipitate? How do you know?

Answer 1

Lead (II) iodide

Step-by-step explanation:

The reaction of lead (II) nitrate, Pb(NO₃)₂ with KI is:

Pb(NO₃)₂(aq) + 2KI(aq) → KNO₃(aq) + PbI₂(s)

This is a typical double-replacement reaction where anions and cations exchange its couple.

All nitrates are solubles, thus, KNO₃ is not the precipitate.

The only possibility of precipitate is PbI₂,

Lead (II) iodide, a yellow and insoluble solid...