does postassium nitrate have a high or slow conductivity

Answer 1

As a crystal, very low.

In solution, I say high conductance, however it is about half as much as solutions of sodium or potassium chloride.

See table 73 in section 81 of this book
http://books.google.com/books?id=ItbQAAAAMAAJ&pg=PA198&lpg=PA198&dq=potassium+nitrate+solution+conductivity&source=bl&ots=sQjXaRYjxI&sig=U7RQLbG5uN2SGj2EE7D2mHyu9UU&hl=en&ei=JSdNS86SN5TKlAfU8PHFAQ&sa=X&oi=book_result&ct=result&resnum=7&ved=0CCgQ6AEwBjgK#v=onepage&q=potassium%20nitrate%20solution%20conductivity&f=false

Answer 2

The melt also has a high conductance.