Question

A careless student forgets to label one of their reagent containers. They know it contains one of the following solutions: 0.1 M NaCl 0.1 M Ca(NO3)2 0.1 M KCH3COO The student decides to add some 0.1 M Pb(NO3)2 to a sample of the reagent in question. Upon stirring, a white precipitate formed. Which of the possible solutions is present in the unlabeled container based on this observation?

A. 0.1 M KCH3COO
B. 0.1 M Ca(NO3)2
C. 0.1 M NaCl

Answer 1

0.1 M NaCl

Step-by-step explanation:

This question reminds of of the solubility rules. Let us recall that all chlorides are soluble except those of lead, mercury II and silver which are insoluble in water.

The following reaction will occur leading to the formation of a precipitate;

Pb(NO3)2(aq) + 2NaCl(aq) -------> 2NaNO3(aq) + PbCl2(s)

The white precipitate formed is PbCl2.