## How did they come up with this completed reaction

This is what the completed reaction looks like
Na2CO3 + 2HCl ⇔ 2NaCl + H2O + CO2

My question is how did they get the products in the above reaction.

Here is my attempt, but I don't see how to get it like in the above reaction
Na2CO3 + HCl ⇔ NaCl + HCO3

The HCO3 breaks down as follows:

HCO3 + H2O ⇔ H3O+ + CO2

So my question is how did they only get H2O + CO2 in the top reaction without the hydronium H3O+ ??

Thanks
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 Quote by lechatelier Here is my attempt, but I don't see how to get it like in the above reaction Na2CO3 + HCl ⇔ NaCl + HCO3
There is a Na missing.

 Quote by lechatelier The HCO3 breaks down as follows: HCO3 + H2O ⇔ H3O+ + CO2
Where does the charge comes from?

 Quote by lechatelier So my question is how did they only get H2O + CO2 in the top reaction without the hydronium H3O+ ??
Apart from what DrS wrote, solution of HCl contains plenty of H+.

## How did they come up with this completed reaction

Well, the first equation you gave us is balanced. The reactants and products both contain:

3 O
2 Na
2 Cl
2 H
1 C

However, your second equation is missing a coefficient in front of one of the reactants. You wrote: Na2CO3 + HCl ⇔ NaCl + HCO3. This is not balanced properly, because on the reactant side you have 2 Na, and on the product side you only account for 1 Na. If you add a two in front of the HCl in the second equation, you get the correct products for the completed reaction of:

Na2CO3 + 2HCl ⇔ 2NaCl + H2O + CO2.
 Heavymetal: It's not a question about balancing!! I could balance the equation no problem. The question is why the reaction doesn't go this route: Na2CO3 + 2HCl ⇔ 2NaCl + H2CO3 The H2CO3 breaks down as follows: H2CO3+ H2O ⇔ H3O+ + HCO3 The HCO3 breaks down as follows: HCO3+ H2O ⇔ H3O+ + CO3 So I got H3O+ + CO3 but why is it that the correct reaction has H2O + CO2 (at the top, at the beginning of this post) without the hydronium ion H3O+ and CO3 ??

 Quote by DrStupid There is a Na missing. Where does the charge comes from?
Are you serious in asking me where the +ive charge on a hydronium ion came from????
 I believe it goes: H2CO3 + 2H2O ⇔ HCO3- + "H3O+" + H2O HCO3- + "H3O+" + H2O ⇔ CO32- + 2"H3O+" CO32- + 2"H3O+" ⇔ 3H2O + CO2 I say "H3O+" because it doesn't actually take shape of the hydronium ion here. So if you cancel out the 2 H2O from the beginning, and the 2 out of the 3 in the end, you get a net equation that looks like: H2CO3 ⇔ H2O + CO2 However, it probably looks more like this: H2CO3 ⇔ HCO3- + H+(aq) HCO3- + H+(aq) ⇔ CO32- + 2H+(aq) CO32- + 2H+(aq) ⇔ H2O + CO2

 Quote by HeavyMetal you get a net equation that looks like: H2CO3 ⇔ H2O + CO2
That's the main equation here, everything else is just an alternative take on the several equilibria present in the solution.

 Quote by lechatelier Are you serious in asking me where the +ive charge on a hydronium ion came from????
Yes, I do. The net quantity of electric charge must not change.