Question

What is the balanced molecular, ionic, and net ionic equation for: Solutions of acetic acid and sodium nitrite are mixed.?

Answer 1

See below.

Explanation:

The reaction between two solutions of acetic acid (`CH_3COOH` and sodium nitrite (`NaNO_2`) could be written in three different ways:

The Molecular equation:
`CH_3COOH(aq)+NaNO_2(aq)->CH_3COONa(aq)+HNO_2(aq)`

The ionic equation:
`CH_3COO^(-)(aq)+H^(+)(aq)+Na^(+)(aq)+NO_2^(-)(aq)->CH_3COO^(-)(aq)+H^(+)(aq)+Na^(+)(aq)+NO_2^(-)(aq)`

The net ionic equation:
`CH_3COO^(-)(aq)+H^(+)(aq)+Na^(+)(aq)+NO_2^(-)(aq)->CH_3COO^(-)(aq)+H^(+)(aq)+Na^(+)(aq)+NO_2^(-)(aq)`

In this case, since all ions are in solution, and remain in solution after mixing, the net ionic equation will be the same as the ionic equation.

Moreover, in a more complex way to explain this, since acetic acid is a weaker acid than nitrous acid, the reaction will favour the side where acetic acid is; which is the left side.

Note that reactions between an acid and a base favour the formation of the weaker acid.

An example where ionic equation would be different than the net ionic equation is the following.
If we mix a solution of silver nitrate (`AgNO_3`) and a solution of sodium chloride (`NaCl`):

The ionic equation:
`Ag^(+)(aq)+NO_3^(-)(aq)+Na^(+)(aq)+Cl^(-)(aq)->AgCl(s)+Na^(+)(aq)+NO_3^(-)(aq)`

The net ionic equation:
`Ag^(+)(aq)+Cl^(-)(aq)->AgCl(s)`

Here the two equations are different because `AgCl` precipitates out of the aqueous solution.

I hope you find this helpful.