What mass of "lead chloride" would result if a 21.5*mL volume of "lead nitrate" at 0.0806*mol*L^-1 concentration were mixed with a 18.00*mL volume of "potassium chloride" at 0.683*mol*L^-1 concentration?

1 Answer
Jun 20, 2017

Under a 2*g mass................

Explanation:

We need (i) a stoichiometric equation.....

Pb(NO_3)_2(aq) + 2KCl(aq) rarr PbCl_2(s)darr+2KNO_3(aq)

Lead chloride is one of the few water-insoluble halides. It crashes out of water solution with alacrity.

And (ii) we need equivalent quantities of each reagent......

"Moles of lead nitrate"=21.5xx10^-3*Lxx0.806*mol*L^-1=0.0173*mol

"Moles of KCl"=18.00xx10^-3*Lxx0.683*mol*L^-1=0.0123*mol.

And thus (clearly) chloride anion is the limiting reagent. Stoichiometry predicts that half an equiv of plumbous chloride will precipitate.

"Mass of" PbCl_2 = (0.0123*mol)/2xx278.10*g*mol^-1

=1.71*g

It is unusual that the chloride ion is in stoichiometric deficiency in that you would think we want to salt out the lead content......