Magnesium chloride (MgCl₂) itself doesn't directly produce a gas. However, when magnesium chloride is subjected to electrolysis, it decomposes and produces chlorine gas (Cl₂) at the anode and magnesium metal (Mg) at the cathode.

Here's the reaction:

MgCl₂(l) → Mg(l) + Cl₂(g)

So, while magnesium chloride doesn't directly release a gas, it can be used to produce chlorine gas through electrolysis.