Question

Which combination will produce a precipitate? agno3 (aq) and ca(c2h3o2)2 (aq) naoh (aq) and hcl (aq) nacl (aq) and hc2h3o2 (aq) nh4oh (aq) and hcl (aq) fe(no3)2 (aq) and koh (aq)?

Answer 1

The combinations that will produce a precipitate are AgNO3(aq) and Ca(C2H3O2)2(aq), Fe(NO3)2(aq) and KOH(aq), and NH4OH(aq) and HCl(aq).

Step-by-step explanation:

When mixing AgNO3(aq) and Ca(C2H3O2)2(aq), a precipitate of AgCl(s) will form. This is because AgCl is insoluble in water. The balanced equation for this reaction is 2 AgNO3(aq) + Ca(C2H3O2)2(aq) → 2 AgCl(s) + Ca(NO3)2(aq).

Another combination that will produce a precipitate is Fe(NO3)2(aq) and KOH(aq). The precipitate formed is Fe(OH)2(s). The balanced equation for this reaction is Fe(NO3)2(aq) + 2 KOH(aq) → 2 KNO3(aq) + Fe(OH)2(s).

Lastly, NH4OH(aq) and HCl(aq) will produce a precipitate of NH4Cl(s). The balanced equation for this reaction is NH4OH(aq) + HCl(aq) → NH4Cl(s) + H2O(l).

Answer 2

The combination that will produce a precipitate is Fe(NO₃)₂(aq) and KOH(aq). The balanced chemical equation shows the production of iron(II) oxide, Fe(OH)₂(s) and potassium nitrate, KNO₃.

Fe(NO₃)₂(aq) + 2KOH(aq) → Fe(OH)₂(s) + 2KNO₃(aq)

Fe(OH)₂ is insoluble in water. It is naturally a white solid but in the presence of even a small amount of oxygen, it turns into a green color. That is why, it is also referred to as "green rust". The other product KNO₃ is an ionic salt that forms an aqueous solution in water.

Other combinations among the choices do not produce a solid. This is based on the solubility rules wherein it is stated that:

1. All compounds of C₂H₃O₂, Na⁺, NH₄⁺ along with other alkali metals are soluble in water.
2. All compounds with Cl are soluble except for Pb, Hg, and Ag.