halacha - talking after washing

1. 
   

   If one talked after washing does he have wash again and is it a hefseik?

   
   


2. 
   

   Where in halachah is it stated that one should preferably not talk after washing?

   
   


3. 
   

   I read that the only time you need to wash again is if you touch the hand of one who didn’t wash, touch a normally covered part of your body or touched feces (as in changing a diaper). Where is the halachic source for this?