Question

A student is given two clear solutions. One solution contained lead ions, Pb2+ and the other solution contains chloride ions, Cl-. When the two solutions are mixed, a clear solution with white powder at the bottom results. What has happen to cause this change?

Answer 1

A chemical change has occurred creating a precipitate. 
Just had that question on a quiz. XP

Hope I helped :)

Answer 2

Answer: A chemical change has occurred.

Explanation: A chemical change is a change which results when there is a change in the chemical composition of the atoms.

Chemical changes are accompanied by:

a) Change in color

b) Absorption or release of heat

c) formation of precipitates

d) production of gas

$Pb^{2+]+2Cl^-\rightarrow PbCl_2(s)$

The white powder is precipitates of lead chloride $PbCl_2(s)$ which do not dissolve.