Question

What is the driving force in the following reaction Ni(NO3)2(aq)_____ NiS(s)+2KNO3(aq)

Answer 1

Answer:

• The driving force is the formation of a precipiate.

Explanation:

The driving force is the formation of the precipiate, NiS(s).

The chemical equation is:

• Ni(NO₃)₂(aq) + K₂S(aq) → NiS(s) +2 KNO₃(aq)

Notice that both reactants, Ni(NO₃)₂(aq) and  K₂S(aq) and the product KNO₃(aq) are in aqueous solutions as ions, while NiS(s) is a solid precipitate

• Ni(NO₃)₂(aq) → Ni⁺²(aq) + 2NO₃⁻ (aq)

• K₂S(aq) → 2K⁺(aq) + S²⁻(aq)

• 2KNO₃(aq) → 2K⁺(aq) + 2NO₃⁻(aq)

When the reactants are combined the total ionic equation that represents the reaction is:

Ni⁺²(aq) + 2NO₃⁻ (aq) + 2K⁺(aq) + S²⁻(aq) → NiS(s) + 2K⁺(aq) + 2NO₃⁻(aq)

In that equation 2K⁺ and 2NO₃⁻ appear both on the reactant side and the product side, then it is said that they are spectator ions and do not intervene in the reaction.

When you cancel them, the net ionic equation is:

• Ni⁺²(aq) + S²⁻(aq) → NiS(s)

Thus, what makes the net reaction is the formation of the precipitate, thus it is said that the driving force of the reaction is the formation of the precipitate, NiS(s).