
Originally Posted by
galexander
There's also the observation that when you dissolve table salt, NaCl, in water the solution still tastes salty.
But if the NaCl has broken up into separate ions in solution how can the solution still taste of salt?
I'm not sure of the
how but perhaps your implied assumption that we can actually taste NaCl when it is a solid might be wrong.
Try this experiment:
What happens when you put solid NaCl into your mouth? It dissolves, yet the salty taste doesn't go away when it does. So, you definitely taste dissolved Na+ and Cl- ions (or at least one of them, anyway).
What happens when you lick a block of solid salt? It tastes salty. Why? I think it is because your saliva dissolves the salt and, again, you are tasting the dissolved ions not the solid NaCl.
In that context, the salty taste of water containing dissolved NaCl makes sense.
But, are you tasting both the Na+ and Cl- ions, or only one of them? I'm not sure, but If you've ever tasted potassium chloride, KCl (which dissolves into separate ions in an aqueous solution, just like NaCl does), it has a different taste so perhaps it is the sodium ion that has produces the familiar "salty" taste of table salt, more than the chloride ion.