GST applicable or not

md sajruddin khan (full details of gst and hsn code)   (233 Points)

06 May 2018  
when we purchase goods before GST (before 01/07/17 in CST),
And I want ro return this stock to co.

then my question is, In debit note 'gst Will be applicable on such stock or not.
If applicable, then How mutch?
and how i adjust it in my a.c.

you are requested to please guide me..