Identify each of the following unbalanced aqueous reactions as an acid/base reaction (a), a redox reaction (r) or a precipitation reaction (p). (Assume that any water soluble reactants and products are at 0.1 M concentration.) Your answer should be a three letter word made up of the letters a, r and p (no commas, no spaces). For example, the response rrr would indicate all three reactions are redox reactions.

a) FeCl2 + (NH4)2S right arrow FeS + NH4Cl
b) NaCN + NH4Cl right arrow NH3 + NaCl + HCN
c) NH3 + HNO2 right arrow N2 + H2O