I was asked to write a balanced chemical equation for the reaction between sulfuric acid and sodium carbonate. The balanced equation isn't the problem. The question asks to also show all the state symbols.

All the equations I find online have sodium carbonate as a solution, not a solid. I'm also aware there are two forms of the balanced equation: $$\ce{H2SO4(aq) + Na2CO3(s) -> H2CO3 + Na2SO4 -> H2O + CO2 + Na2SO4}$$ So do I say the sodium sulfate is a solid or in solution?

  • $\begingroup$ I guess Carbon dioxide is not the problem? So ask yourself what would happen if you put Sodium sulphate in water. Also $\ce{H2CO3}$ is never stable in water. $\endgroup$ Apr 14, 2014 at 10:14
  • $\begingroup$ Thanks, that helps :-) It just feels better to double check. $\endgroup$ Apr 14, 2014 at 10:38
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    $\begingroup$ As best practice share always what's your hypothesis. What do you think: is a solid or goes in solution? For us will be easier to help you to gasp the concept... $\endgroup$
    – G M
    Apr 14, 2014 at 11:25

2 Answers 2


Try to follow this reasoning. (mouse over for answer)

Which parameter is mandatory to determine if a substance precipitate or not?


How does this parameter behave with sulphates?

Many sulphates are soluble in water. Generally the sulphates become less soluble as you go down the group. So sodium sulphate is surely soluble, confirm with Wikipedia.

Additionally think about others parameters that can have some sort of influence in this to improve your understanding of chemistry. So which parameters can affect this behavior?

In fact as best practice you should always take in account the temperature and the amount of substance, and if the solution is saturated the excess will precipitate.

What's the answer?



The answer depends on the reaction stoichiometry, reactant concentrations, and temperature. As written and unless concentrated, $\ce{CO2}$ fizzes off and everything stays dissolved. With excess acid you'll get sodium bisulfate. Concentrated and cooled, you can precipitate sodium sulfate decahydrate (Glauber's salt), M.P. = $32.38 ~\rm^{\circ} C$. That is an interesting M.P. standard and constant temperature bath during the phase transition. There is also a heptahydrate.

Sodium sulfate phase diagram


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