Question

Which of the following are strong electrolytes?
BaCl2
AgNO3
PbI2
Pb(NO3)2
KI

I think they are all strong electrolytes. Is this correct?

Answer 1

PbI2 is an insoluble salt. See the solubility rules.
http://www.files.chem.vt.edu/RVGS/ACT/notes/solubility_rules.html