To calculate the number of moles in 2.3 x 10^23 formula units of NaCl, we need to use Avogadro's number, which is approximately 6.022 x 10^23 particles (atoms, molecules, or formula units) per mole.

Therefore, the number of moles in 2.3 x 10^23 formula units of NaCl is:

Moles of NaCl = (2.3 x 10^23 formula units) / (6.022 x 10^23 formula units/mole)

= 0.382 moles

So, there are approximately 0.382 moles in 2.3 x 10^23 formula units of NaCl.