Draw both resonance forms of the nitrite ion, no2–. be sure to include all lone pairs and non-zero formal charges. do no add curved arrows to structures. do not add an arrow or plus sign between the structures.

The lewis structure of Nitrile Ion is drawn as,

Step 1) Add all the valence electrons of each element present in molecular ion.

               Valence Electrons of N   =  5

              Valence Electrons of O₁  =  6

              Valence Electrons of O₂  =  6

One electron for negative charge  =  1
                                                    -------------
Total valence electrons                     18

Step 2: Draw the Nitrogen atom as central atom surrounded by oxygen atoms. Now connect central atom with oxygen atoms via single bonds and subtract two electrons per single bond from total valence electrons . i.e.

                                                        18
                                                    -     4
                                                       -------
                                                        14

Divide these 14 electrons on each element starting from most electronegative atom to complete its octet. A single lone pair will diminish on formation of the second bond.

The lewis structure of Nitrilte ion with two isomeric forms is given below, each element is given a single colour to show that the nuclei position remains the same during resonance.

The coefficients are 1, 6, 2 and 3

Explanation:

Law of conservation of mass states that mass can neither be created nor be destroyed but it can only be transformed from one form to another form.  

This also means that total mass on the reactant side must be equal to the total mass on the product side.

For the given chemical reaction, the balanced equation follows:

By Stoichiometry of the reaction:

1 mole of aqueous solution of aluminium sulfate reacts with 6 moles of aqueous solution of potassium hydroxide to produce 2 moles of aqueous solution of aluminium hydroxide and 3 moles of aqueous solution of potassium sulfate

Hence, the coefficients are 1, 6, 2 and 3