First Adjust your Chrome settings to choose your preference.
A. Go to Settings from the top RHS menu in Chrome. Settings is near the ottom of that menu.
B. Choose "Privacy and Security"
C. Choose PDFs
D. Set Downlaod as the action you require as default
Make Adobe Acrobat your default PDF application
It probably already is. However, if not, this is achieved by making Adobe your default app for PDF files (see this article on how to do it for Outlook and mail messages and apply the same principle).