First of all, it's properly written NaCl, NaOH, HCl, HOH.
NaCl is Sodium Chloride or table salt.
NaOH is Sodium Hydroxide, a 14 on the pH scale (most basic).
HCl is Hydrochloric acid, a 0 on the...
4.5 moles NaCl = 4.5000000000001 formula units NaCl *******************2nd Opinion************* 4.5 moles of NaCl would contain 4.5 x (6.02 x 1023) formula units. = 2.7 x 1024 formula units