A white solid is known to consist of one or more of the following compounds: AgNO3 , Na2CO3, CaCl2, and Pb(NO3)2. A sample of the solid is treated in the following manner: When cold water is added and the mixture is stirred, a white precipitate formed in the solution which remains even after the solution is boiled. The solution is centerifuged and decanted. The precipitate is separated into two parts, which are then treated as follows: When cold 3M HNO3 is added to one part until the solution is acidic, the precipitate remains, even after heating to boiling. For each solid, indicate wheter these results indicate the presence or absence from the sample.