The following list contains some common polyatomic ions. Using the charge on these ions and the idea of valence, predict the formulas for the following.


nitrate NO3 - phosphate PO4³-

sulfate SO4²- acetate C2H3O2 -

ammonium NH4 4 chromate CrO4²-

carbonate CO3²- dichromate Cr2O7²-

permanganate MnO4 - sulfide S²-

sodium carbonate

potassium permanganate

Verified Answer :

sodium carbonate - chemical formula:  Na2CO3
- water-soluble sodium salt of carbonic acid with alkalinizing property
- also known as Disodium carbonate or Carbonic acid disodium salt
 
potassium permanganate - chemical formula:  KMnO4
- inorganic chemical compound and is used for medication
- 
purplish colored crystalline solid
- noncombustible but accelerates the burning of combustible materials

Answer: \(Na_2CO_3\) or Sodium carbonate.

              \(KMnO_4\) or Potassium permanganate

Sodium ion carries 1 + charge whereas carbonate ion carries overall charge of -2. So for every carbonate ion, two sodium ions combine to balance the charges and thus form a stable compound, \(Na_2CO_3\)

Potassium ion carries 1 + charge where as permanganate ion carries overall charge of -1. So for every permanganate ion, one potassium ion combines to balance the charges and thus form a stable compound,  \(KMnO_4\)

The predicted formulas are shown in the attached image.


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