13. An aqueous solution contains 0.60 mol of KCl and 1.20 mol NH4Cl. What is the minimum number of moles of Pb(NO3)2 that must be added to precipitate all of the chloride ions?
a. 0.60 mol
b. 0.30 mol
c. 0.45 mol
d. 0.90 mol
Answer:
PrecipitationStep-by-step explanation:
Here we are having chloride ions from two salts
1 - KCl----> K+. + Cl-
2- NH4Cl----> NH4. + Cl-
But for the net ionic equation, we represent ONLY the net, macroscopic chemical change:
Pb2++2Cl−→PbCl2(s)⏐↓
PbCl2 is a white salt that is fairly insoluble in aqueous solution.
It means 1 mole of Cl- ions require 2 moles of Cl-
We have total Cl- = 0.6 + 1.20
= 1.80 moles
So 0.9 moles of PbNO3 is required