Compared to distilled water, an aqueous salt
solution has
(1) better electrical conductivity
(2) poorer electrical conductivity
(3) a lower boiling point at standard pressure
(4) a higher freezing point at standard pressure

I think the correct answer is option 1. Aqueous salt solution has better electrical conductivity than distilled water. When salt is in aqueous form, ions forms that move freely through the solution. This will enable current to flow freely in the solution.

Ithink about 50 % of an original isotope's number of atoms remain