BALANCINGOF CHEMICAL EQUATION, another example, NEUTRALIZATION REACTIONS, PRECIPITATION REACTIONS, REDOX REACTIONS,

 

ANSWER:

            Empirical formula = NiSO⁴

 

BALANCINGOF CHEMICAL EQUATION:

            According to law of conservation of mass atoms can neither be created nor be destroyed in a chemical reaction but they can be converted from  one to another form. Therefore in a chemical equation we should have same number of atoms of each element on both sides of the equation. Doing this is called balancing of chemical  equation. In doing so the formula of the reactants and the products are not altered, only the total number of moles may be charged. The equation may be balanced by multiplying any species with whole number or fraction number, this number stands for number of moles. e.g;

 

            2NH₃ + 5/2O₂                                    2NO + 3H₂O

 

            2NH₃ + 2.5O₂                         2NO + 3H₂O

 

            4NH₃ + 5O₂                            4NO + 6H₂O

 

Similarly

            C₄H₁₀ + 13/2O₂                      4CO₂ + 5H₂O

            C₄H₁₀ + 6.5O₂                         4CO₂ + 5H₂O

            2C₄H₁₀ + 13O₂                        8CO₂ + 10H₂O

 

another example

            2Pb(NO₃)₂                              2PbO + 4NO₂ + O₂

 

IONIC EQUATION:

            In some situations instead of writing full equation, it is preferred to write ionic equation. Such equations are simpler than the full equations. Ionic equations are preferred to write for neutralization, precipitation and redox reaction. In neutralization and precipitation reactions aqueous ions from both sides are canceled out, whereas ions undergo change of state are represented in the ionic equation.

 

NEUTRALIZATION REACTIONS:

            Such relations are represented in ionic form by deleting aqueous ions on both sides.

                        CHl_(aq) + NaOH_(aq)                              NaCl_(aq) + H₂O₍₁₎

            Ionic form

                        H⁺_(aq) + Ol_(aq)                                       H₂O₍₁₎

 

PRECIPITATION REACTIONS:

            In precipitation reactions, aqueous ions from both sides of the equation are cancelled out, whereas ions undergo the change of precipitation only are represented.

                        NaCl_(aq) + AgNO_3(aq)                                        AgCl_(s) + NaNO_3(aq)

            Ionic equation

                        Cl^-1_(aq) + Ag⁺_(aq)                                               AgCl_(s)

Similarly;

                        CuSO_4(aq) + 2NaOH_(aq)                                    Cu(OH)_2(s) + _Na2SO4(aq)            

I           onic form

                        Cu⁺_(aq) + 2OH^-1 _(aq)                                          Cu(OH)_2(s)

REDOX REACTIONS:

            In redox reactions the ions which undergo the change in oxidation state are only represented whereas the ions which remain one anged are cancelled out on both sides.

                        Zn⁰ + Cu^-2SO₄^-2                                               Zn⁺²SO₄^-2 + Cu⁰

Ionic equation;

                        Zn⁰ + Cu⁺²                                                             Zn⁺² + Cu⁰

Another example;

                        MnO₄^-1 + 8H⁺¹ + 5e                                        Mn⁺² + 4H₂O

 

            Source of electron is certainly a reducing agent like Fe⁺², therefore;

                        MnO₄^-1 + 8H⁺¹ + 5Fe⁺²                                  Mn⁺² + 4H₂O + Fe

            Similarly;

                        Cr₂O₇^-2 + 14H⁺¹ + 6e^-                                     2Cr⁺³ + 7H₂O

           

            In an ionic equation the overall charge on the ions on both sides of the equation must be balanced.

            Some more examples are;

                        C_-2 + 2Br^-1                                           2Cl^-1 + Br₂

 

                        2Fe^-3 + 2l^-1                                          2Fe⁺² + l₂

 

                        Zn + 2H⁺¹                                           Zn⁺² + H₂

            Ionic equation therefore provides a shorter equation which focuses our attention on the change taking place.