# Net ionic equation (need help)

1. Feb 21, 2006

### francisco

i need help with the following problem:

rewrite the following unbalanced equation, changing it to a balanced net ionic equation.

Mg (s) + HC2H3O2 (aq) --> Mg(C2H3O2)2 (aq) + H2 (g)

thanks.

francisco

2. Feb 24, 2006

### francisco

Mg (s) + HC2H3O2 (aq) --> Mg(C2H3O2)2 (aq) + H2 (g)

i balance the equation:

Mg (s) + 2HC2H3O2 (aq) --> Mg(C2H3O2)2 (aq) + H2 (g)

then i write the equation, listing all the species present in solution.

Mg (s) + 2H(+) (aq) + (C2H3O2)2(2-) (aq) --> Mg(2+) (aq)
+ (C2H3O2)2(2-) (aq) + H2 (g).

i see that (C2H3O2)2(2-) undergoes no change during the reaction. it appears on both sides of the reaction arrow and acts merely as a spectator ion, whose only role is to balance the charge. the actual reaction, when stripped to its essentials, can be described more simply by writing the following ionic equation, in which the spectator ion
(C2H3O2)2(2-) is removed:

Mg (s) + 2H(+) (aq) --> Mg(2+) (aq) + H2 (g).

leaving the spectator ion (C2H3O2)2(2-) out of the net ionic equation merely implies that the specific identity of the spectator ion is not important: any nonreactive ion could fill the same role.

is this correct?

thanks.

francisco

Last edited: Feb 24, 2006
3. Feb 25, 2006

### ksinclair13

Nicely done!

4. Feb 26, 2006

### Staff: Mentor

It is not a (C2H3O2)2(2-) but 2C2H3O2(-). Small, but very important difference.

Best,
Borek

Last edited by a moderator: Aug 13, 2013
5. Sep 23, 2009

Hi everyone.I'm having some great trouble.I need to know how to write the net ionic equation for: Mg + Pb(NO3)2=Pb + Mg(NO3)2..