Albert and Bernard just became friends with Cheryl, and they now know when her birthday is! They see that she is holding a test tube containing a solution and a precipitate, which she tells them that she has produced by mixing two 0.02 M aqueous solutions. They want to know what precipitate she has produced. Cheryl gives them a list of possible cations and anions present in the original solutions: Na+, Ag+, Ba2+, Mg2+, OH–, CO32–, Cl–, SO42–. She tells Albert the identity of the anion present in the precipitate and Bernard the identity of the cation present in the precipitate.
Albert: I don’t know what the precipitate is.
Bernard: I didn’t, but now that you’ve said that, I do.
Albert: Then so do I.
What is the precipitate?