Fonty is right.
Adding anything to a fast apart from water is feeding and classified as a reducing diet.
Common table salt (sodium chloride) is a poison anyway and to be avoided at all costs.
Why do you suppose you feel thirsty after a salty snack? A. The body recognizes it as a poison and demands more water to expel it.
Sodium chloride is just not the way to get the sodium your body needs.