Question

Concept:

During the first week of this project, you need to synthesize several common kidney stones by precipitation reactions (Make sure that you save the kidney stones for week 2). You need to choose the reactants in a way that the kidney stone is the only product that precipitates out from the solution, while all other products remain soluble in water. This way the precipitate (kidney stone) can be separated from the rest of the solution by either filtration or centrifugation, followed by drying and weighing. Therefore, it is crucial to choose proper reactants for the precipitation reactions.

For example, to synthesize BaSO₄ precipitate, you could mix a MgSO₄ solution with a Ba(NO₃)₂ solution as reactants to produce a BaSO₄ precipitate (solubility is 0.0002448 g/100 mL at 20 �C) and a Mg(NO₃)₂ soluble salt (see Equation 1). Since BaSO₄ is the only precipitate of the two products, itcan be readily separated from the rest of the solution.

MgSO₄(aq) + Ba(NO₃)₂(aq) --> Mg(NO₃)₂(aq) + BaSO₄(s)   (Equation 1)

Question:

Suppose you need to make the following four precipitates (by four different precipitation reactions): CaCO₃, Ca₃(PO₄)₂, CaC₂O₄, and AgCl. For each reaction, one reactant is given, and you need to choose the other reactant from the drop-down box in a way that the precipitate that you need to make is the only precipitate of the products. A solubility table is given below for your reference. The letter �S� indicates that the compound formed from the cation and anion is soluble in water, and the letter �I� indicates that the compound formed from the cation and anion is insoluble in water (The term �insoluble� is often used to describe poorly or very poorly soluble compounds with very low solubility at a given temperature, which does not mean that the solubility is zero. In Question 8, you will learn that there are methods to increase solubility).

	NO3?	CO32?	C2O4�2?	Cl?	PO43?
Ca2+	S	I	I	S	I
Na+	S	S	S	S	S
NH4+	S	S	S	S	S
Ag	S	I	I	I	I

Note: S = Soluble; I = Insoluble (forming precipitate)

1. Synthesis of CaCO3: Ca(NO3)2
2. Synthesis of Ca3(PO4)2: Ca(NO3)2

3. Synthesis of CaC2O4: Ca(NO3)2

4. Synthesis of AgCl: AgNO3

Please answer #1-4 . These are the choices for all four, please pick 1 for each :

Na3PO4

NaH2PO4

NaCl

NH4NO3

Mg(NO3)2

Na2C2O4

Na2CO3

Answer 1