Question

When each of the following pairs of aqueous solutions is mixed, does a precipitation reaction occur? If so, write the formula and name of the precipitate. (Type your answer using the format CO2 for CO2. Type NONE in the blanks if there is no precipitation reaction.)

(a) iron(III) bromide + potassium phosphate formula . name .

(b) silver nitrate + sodium bromide formula . name . .

Answer 1

Solubility rules:

- Most alkali metal (group I metals) are always soluble

- Cations/Anions such as NH4+, HCO3-; ClO3-, NO3- are always soluble

- Most halides are soluble, F-,Cl-,Br-,I-, exceptions = Ag+, Hg2+2, Pb+2 compounds

- Most sulfates are soluble (SO4-2); exceptions = Ag+, Ca+2, Sr+2, Ba+2, Hg2+2, Pb+2 compounds

- In general (except all alkali metals) these ions will NOT be soluble: PO4-3, CrO4-2, S-2, CO3-2

a)

iron(III) bromide = FeBr3(aq)

potassium phosphate =K3PO4(aq)

FeBr3(aq) + K3PO4(aq)

ions present, Fe+3 and PO4-3 are likely to form FePO4(s) and all other remain in ions

equation

FeBr3(aq) + K3PO4(aq) --> FePO4(s) + 3KBr(aq)

b)

silver nitrate = AgNO3(aq)

sodium bromide = NaBr(aq)

Halides of silver will form precipitate, AgBr(s)

AgNO3(aq) + NaBr(aq) = AgBr(s) + NaNO3(aq)