A Solid Laboratory Sample Contains Two Substances, Lead(II)carbonate and Potassium

Multiple Choice

A solid laboratory sample contains two substances, lead(II) carbonate and potassium carbonate. A 5.000 g sample of this unknown was treated with aqueous nitric acid to dissolve it, then, after further treatment to adjust the acidity, it was treated with an excess of potassium chromate solution. The precipitate which formed, when dried carefully and weighed, has a mass of 2.697 grams. Calculate the percent, by weight, of lead(II) carbonate in this laboratory sample. Hint: You should write out each reaction on paper and work backwards through the reactions.

A) 44.60 %
B) 50.00 %
C) 65.91 %
D) 72.93 %
E) 77.38 %