# In the reaction between HCl and Na_2CO_3, what gas is formed?

Dec 14, 2015

Carbon dioxide.

#### Explanation:

Sodium carbonate, ${\text{Na"_2"CO}}_{3}$, will react with hydrochloric acid, $\text{HCl}$, to produce sodium chloride, a

soluble ionic compound that exists as ions in solution, and carbonic acid, ${\text{H"_2"CO}}_{3}$.

Now, carbonic acid molecules are highly unstable in aqueous solution, so they actually decompose to form carbon dioxide, ${\text{CO}}_{2}$, which bubbles out of solution, and water.

You can thus say that you have

${\text{Na"_2"CO"_text(3(aq]) + 2"HCl"_text((aq]) -> 2"NaCl"_text((aq]) + "H"_2"CO}}_{\textrm{3 \left(a q\right]}}$

But since

${\text{H"_2"CO"_text(3(aq]) rightleftharpoons "H"_2"O"_text((l]) + "CO}}_{\textrm{2 \left(g\right]}} \uparrow$

Your overall reaction will look like this

${\text{Na"_2"CO"_text(3(aq]) + 2"HCl"_text((aq]) -> 2"NaCl"_text((aq]) +"H"_2"O"_text((l]) + "CO}}_{\textrm{2 \left(g\right]}} \uparrow$

The net ionic equation, for which spectator ions are omitted, will look like this

${\text{CO"_text(3(aq])^(2-) + 2"H"_text((aq])^(+) -> "H"_2"O"_text((l]) + "CO}}_{\textrm{2 \left(g\right]}} \uparrow$