Question

if we given a distiled water and a blue litmus paper how can we find it is in which character
 ?

Answer 1

if it turns to red then it is acid otherwise it is base

Answer 2

if we put the red litmus paper in the distilled water then if it is basic it will change into blue and will not change color in the blue litmus paper but if it is acidic it will change it's color in blue litmus paper it will convert into red color and in red litmus paper it would not change it's color. 
   i hope that this will help u..................^_^