What is the reaction between Magnesium chloride and Sodium bicarbonate? For some reason it has been very difficult to find the right answer for this question as there's so much conflicting information to be found online. Some mention a reaction where carbonic acid is made, others mention carbonates and hydroxide end product but nothing seems to be precise. 

But can the reaction be as simple as this (a double displacement reaction) where magnesium bicarbonate and sodium chloride are the end products:
$$
\ce{2NaHCO3 + MgCl2 -&gt;  2NaCl + Mg(HCO3)2}
$$
Having actually perform this reaction, I can say with certainty that when you mix aqueous sodium bicarbonate with aqueous magnesium chloride, there is no apparent reaction. This is consistent with an equilibrium reaction (actually, just ions): 

$$\ce{2 NaHCO3 + MgCl2 &lt;=&gt; 2 NaCl + Mg(HCO3)2}$$

However, upon brief heating in a microwave (for example), a white precipitate of magnesium carbonate develops indicating the reaction has moved to the right. 

$$\ce{2 NaHCO3 + MgCl2 -&gt;[Heat] 2 NaCl + MgCO3(s) + CO2 (g) + H2O}$$