why does two soluble salts react when mixed together? like NaCO3 and ZnNO3?

Answer 1

it depends on the reactivity of the metal in this example sodium will replace zinc because it is more reactive this is called displacement reaction or double replacement reaction

Answer 2

It depends on the concentrations of each salt. The solubility of each ion pair is determined by their solubility product. The solubility products of sodium carbonate and zinc nitrate are presumably sufficiently high for them to be regarded as being "soluble". But when they dissolve they each dissociate into ions and mixing these two solutions together will effectively add the solubility products of zinc carbonate and sodium nitrate into the mixture. If one of these solubility products is lower than the amount of ions in solution it will cause that salt to precipitate out until all the conditions of the solubility products are satisfied. You will be left with a saturated solution with respect to the ion pair that precipitated. In practice, things will be more complex than this since pH will have an effect (so you have to consider carbonate:bicarbonate equilibria), temperature will have an effect and there is also the possibility of precipitating a mixed salt. The number of possible reactions in such systems can quickly result in quite complex equilibria being set up.
This is one reason why the composition of the oceans is nominally constant (it varies a lot locally due to rivers, evaporation etc.) because the complex mix of salts means that many ion pairs are saturated and while salts are being added from rivers they are also being removed by precipitation somewhere else. This is one mechanism by which managanese nodules on the ocean floor grow and is one of several counter arguments to creationist claims that the ocean salinity is an indication that the Earth is only ~6,000 years old.

Answer 3

Your formula for Sodium Carbonate is it should be Na2CO3.
Similarly Zinc Nitrate should be Zn(NO3)2
In solution the chemicals disassociate into their respective ions.
These ions are free to recombine in other way like NaNO3 an ZnCO3 .
If one of these re-associated compounds is insoluble to a greater degree, then it will precipitate out of solution.

Answer 4

Lancenigo di Villorba (TV), Italy

I AGREE NOT WITH PREVIOUS ANSWERS.

1st Error)
Sodium carbonate is a bi-valent chemical compound. Hence, you must write Na2CO3 instead NaCO3.

2nd Error)
Zinc nitrate is a bi-valent chemical compound. Hence, you must write Zn(NO3)2 instead ZnNO3.

3rd Error)
In wet chemical essays, zinc soluble salts may highlighted by MILD ALKALY's dosing, e.g. aqueous solutions of sodium carbonate.
Hence, your question interests a reaction involving Na2CO3 and Zn(NO3)2. What is happens?
You may obtain two different chemical compounds, e.g. so-called BASIC ZINC CARBONATE as white flaky gel.
2 Zn(NO3)2(aq) + 3 Na2CO3(aq) + 2 H2O (aq) --->
---> Zn2CO3(OH)2(s) + 4 NaNO3(aq) + 2 NaHCO3(aq)
WARNING! You cannot see nothing if you dose strong alkalies, e.g. sodium hydroxide.

I hope this helps you.

Answer 5

Double replacement takes place when the products are more stable than the reactants.
2ZnNO3+Na2CO3---> 2NaNO3 +Zn2CO3, a precipitate