Question

Is sodium chloride a mixture?

Answer 1

Sodium chloride solid is not a mixture. It is a pure substance... It cannot be physically separated into its components, `"Na"^(+)` and `"Cl"^(-)`. It would require energy input, and that is clearly not a physical means.

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However, if for some reason, you meant `"NaCl"(aq)`... then sodium chloride IN WATER is a mixture, occurring through the physical dispersion of a liquid solvent amongst the ions, `"Na"^(+)` and `"Cl"^(-)`, that dissociate in solution, surrounding them to separate them from each other.

https://media1.britannica.com/

As a further note, the ions were held together by electrostatic attractions in a lattice, so no chemical change actually occurred!

https://cnx.org/

And in water, this gives:

http://chem.wisc.edu/

(This qualifies as a mixture, since evaporation allows reformation of sodium chloride solid again, thus separating the components, `"NaCl"` and `"H"_2"O"`, via physical means. It is known as a homogeneous mixture.)