a. Pb(NO₃)₂(aq) + Na₂SO₄(aq) → PbSO₄(s) + 2NaNO₃(aq)
b. NiCl₂(aq) + 2NH₄NO₃(aq) → Ni(NO₃)₂(aq) + 2NH₄Cl(aq)
c. FeCl₂(aq) + Na₂S(aq) → FeS(s) + 2NaCl(aq)
d. MgSO₄(aq) + BaCl₂(aq) → MgCl₂(aq) + BaSO₄(s)
a. When lead(II) nitrate (Pb(NO₃)₂) reacts with sodium sulfate (Na₂SO₄), a precipitation reaction occurs. The balanced chemical equation is:
Pb(NO₃)₂(aq) + Na₂SO₄(aq) → PbSO₄(s) + 2NaNO₃(aq)
In this reaction, lead(II) sulfate (PbSO₄) is the insoluble precipitate that forms. The net ionic equation, which only includes the species that actively participate in the reaction, is:
Pb²⁺(aq) + SO₄²⁻(aq) → PbSO₄(s)
b. When nickel(II) chloride (NiCl₂) reacts with ammonium nitrate (NH₄NO₃), no precipitation reaction occurs. Instead, a double displacement reaction takes place. The balanced chemical equation is:
NiCl₂(aq) + 2NH₄NO₃(aq) → Ni(NO₃)₂(aq) + 2NH₄Cl(aq)
In this reaction, nickel(II) nitrate (Ni(NO₃)₂) and ammonium chloride (NH₄Cl) are formed. There is no precipitate formed, so the net ionic equation remains the same as the balanced equation.
c. When iron(II) chloride (FeCl₂) reacts with sodium sulfide (Na₂S), a precipitation reaction occurs. The balanced chemical equation is:
FeCl₂(aq) + Na₂S(aq) → FeS(s) + 2NaCl(aq)
In this reaction, iron(II) sulfide (FeS) is the insoluble precipitate that forms. The net ionic equation is:
Fe²⁺(aq) + S²⁻(aq) → FeS(s)
d. When magnesium sulfate (MgSO₄) reacts with barium chloride (BaCl₂), no precipitation reaction occurs. Instead, a double displacement reaction takes place. The balanced chemical equation is:
MgSO₄(aq) + BaCl₂(aq) → MgCl₂(aq) + BaSO₄(s)
In this reaction, magnesium chloride (MgCl₂) and barium sulfate (BaSO₄) are formed. There is a precipitate formed, which is barium sulfate (BaSO₄). The net ionic equation is:
Ba²⁺(aq) + SO₄²⁻(aq) → BaSO₄(s)