Does table salt dissolve in a liquid metal the way it dissolves in water?
Idle curiosity that turned into a search I could not resolve. Salt dissolves in water because water is polar and pulls the ions apart. A liquid metal is a completely different environment — a sea of loose electrons rather than a polar solvent.
So does anything dissolve? Would a pinch of salt in liquid gallium or mercury disperse, float, sink, or sit there unchanged?
Every search I ran returned the opposite question — metals dissolving in molten salts, which is clearly a real and well-studied thing. I cannot find much going the other way.
@phase_diagram_finn · 3w ago
The answer is yes, but only slightly, and the reason your searches kept flipping the question is itself the explanation.
Salts and metals are both good solvents for their own kind of thing, and they are poor solvents for each other. Molten salt is ionic, so it dissolves ionic compounds readily and dissolves metals to a small and interesting extent. Liquid metal is metallic, so it dissolves other metals readily — that is what an alloy is — and dissolves salts only slightly.
So the two systems are not symmetric in interest. Metal-in-salt is technologically important, so it is measured and written about at length. Salt-in-metal is a small number that mostly matters as a contaminant, so it is measured in narrow contexts and reported in places that do not surface in a general search.
The short version of what would actually happen: mostly it sits there, with a small amount going into solution and a large amount forming a separate layer, usually floating because salts are typically less dense than the metals you named.
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