Question

Consider the reaction when aqueous solutions of cobalt(II) bromide and iron(III) nitrate are combined. The net ionic equation for this reaction is: ?

Answer 1

`"CoBr"_2("aq") + "Fe(NO"_3)_3("aq")"` `rarr` `"no reaction"`

Explanation:

The supposed equation is:

`"3CoBr"_2 + "2Fe(NO"_3)_3"` `rarr` `"3Co(NO"_3)_2 + "2FeBr"_3"`

However, if you consult a solubility table, such as the one below, you will see that all of the species are aqueous. There is no precipitate, insoluble gas, or water, so this reaction does not occur.

`"3CoBr"_2(color(red)"aq") + "2Fe(NO"_3)_3(color(red)"aq")"` `rarr` `"3Co(NO"_3)_2(color(red)"aq") + "2FeBr"_3(color(red)"aq")"`

The correct "equation" is:

`"CoBr"_2("aq") + "Fe(NO"_3)_3("aq")"` `rarr` `"no reaction"`

What you have is a mixture of ions: `"Co"^(2+)("aq")",` `"Br"^(-)("aq")",` `"Fe"^(3+)("aq")",` and `"NO"_3^(-)("aq")"`.