The function of `ZnCl_(2)` in Lucas test for alcohols is `:`

The function of ZnCl_(2) in Lucas test for alcoholsis:

The function of ZnCl_(2) in Friedal Craft's reaction is

What is the function of anhydrous ZnCl2 in Lucas test for distinction between 1^(@) , 2^(@) and 3^(@) alcohols?

Write Luca's test.

What is the function of anhydrous ZnCl_(2) in Luca's test ?