Chemistry - Why does salt dissolved in water taste like salt? If it's just Na+ and Cl- ions
Solution 1:
When you taste salt, you're not pushing crystalline $\ce{NaCl}$ into your taste buds. It dissolves in your saliva and dissociates. When one tastes salt, the saltiness taste receptors respond specifically to the sodium cation. That type of taste receptor is a cation channel. This is why lithium and potassium cations also taste salty (though they also stimulate other receptors which make them taste somewhat different).
There seem to be at least two types of receptors that respond to saltiness. One responds almost specifically to sodium at low concentrations, but at higher concentrations, the other type responds to many cations. See here
Solution 2:
Have you ever tasted salt that was not dissolved in water? Think about this. Have you ever tasted ANYTHING that was not dissolved in, or in contact with, water? The answer is "No", unless you have the worst case of chronic dry mouth ever to exist in the history of humanity, and if you do have that terrible case of dry mouth, you no longer taste anything.
This is because everything you taste is sampled by your taste buds after having samples of its molecules transported through pores on your tongue by water. No water, no taste. And saliva, of course, is mostly water. If you place a dry grain of salt on your tongue, saliva immediately dissolves a bit of it, and transports that salt through taste pores, where receptors in your taste buds report its flavor.
Solution 3:
I'm not a biology expert, so I'm not sure how the $\ce{Na+}$ and $\ce{Cl-}$ ions actually activate certain taste receptors in your tongue such that you can taste the $\ce{Na+}$ and $\ce{Cl-}$ ions.
However, for the chemistry part, do remember that even when you are putting solid $\ce{NaCl}$ into your mouth, the saliva in your mouth will dissolve it, resulting in the breaking of the ionic bond between $\ce{Na}$ and $\ce{Cl}$. Sodium chloride is so soluble that even a tiny drop of water could dissolve a significant amount of salt - probably more than what you would put into your food.
Therefore, it doesn't really matter if you taste solid sodium chloride or sodium chloride solution - they will all taste the same, but perhaps varying in intensity.
Interestingly, if you are able to find a sodium chloride crystal large enough, and ensure that your tongue is dry enough, I believe(again I'm not a biology expert) that you would not be able to taste the sodium chloride, as solid crystals cannot diffuse as easily into your tongue and activate the sodium channels.