Actually this depends on what kind of titration is being
done. If we are titrating Ba(OH)2 using an acid, it actually does not matter
that some Pb(OH)2 is formed because the acid will still neutralize even those
OH- ions that combined with lead Pb.
But other than that, generally we can say that the
calculated concentration can be affected because lead (II) chloride would
co-precipitate with Ba(OH)2 to form Pb(OH)2
