Question

Which pair of aqueous solutions will form a precipitate when mixed?

A: NH4NO3(aq) + Li2CO3(aq)

B: Hg2(NO3)2(aq) + LiI(aq)

C: NaCl(aq) + Li3PO4(aq)

D: AgC2H3O2(aq) + Cu(NO3)2(aq)

Please explain why the answer would be a precipitate

Answer 1

A) Writing the balanced chemical reaction of the given pair of aqueous solutions,

NH₄NO₃(aq) + Li₂CO₃(aq) (NH₄)₂CO₃(aq) + 2LiNO₃(aq)

From the solubility chart,

Carbonates of group 1 elements and ammonium(NH₄⁺) ions will form soluble compounds.

Nitrates of all elements are soluble.

It means No precipitate will form.

B) Writing the balanced chemical reaction of the given pair of aqueous solutions,

Hg₂(NO₃)₂(aq) + 2LiI(aq) Hg₂I₂(s) + 2LiNO₃(aq)

From the solubility chart,

Halides( Cl^-, Br^-, I^-) when combined with Ag+, Pb^2+, and Hg₂²⁺, form insoluble compounds.

Nitrates of all elements are soluble.

It means precipitate will form.

C) Writing the balanced chemical reaction of the given pair of aqueous solutions,

NaCl(aq) + Li₃PO₄(aq) Na₃PO₄(aq) + 2LiCl(aq)

From the solubility chart,

Phosphates of group 1 elements and ammonium(NH₄⁺) ions will form soluble compounds.

Halide compounds are soluble except combined with Ag+, Pb^2+, and Hg₂²⁺.

It means No precipitate will form.

d) Writing the balanced chemical reaction of the given pair of aqueous solutions,

AgC₂H₃O₂(aq) + Cu(NO₃)₂(aq) AgNO₃(aq) + Cu(C₂H₃O₂)₂(aq)

From the solubility chart,

All acetate compounds are soluble.

All nitrate compounds are soluble.

It means No precipitate will form.

Thus, Option B) Hg₂(NO₃)₂(aq) + 2LiI(aq), this pair will form a precipitate when mixed.