Question

A 1.0 l sample of an aqueous solution contains 0.10 mol of nacl and 0.10 mol of cacl2. what is the minimum number of moles of agno3 that must be added to the solution in order to precipitate all of the cl- as agcl(s)? (assume that agcl is insoluble.) 0.10 mol 0.20 mol 0.30 mol 0.40 mol 0.60 mol

Answer 1

0.1 mol of NaCl will produce 0.1 mol of Cl ions while 0.1 mol of CaCl2 will produce 0.2 mol of Cl ions. 

Therefore the total number of mol of  Cl ions is 0.3 mol.

AgNo3    +      Cl(ion form)       ------------->           AgCl      +       Ag(ion form)

Therefore 0.3 mol of Cl ions require 0.3 mol of AgNo3.