[LiquidSummer]

Extra protection as opposed to opening it in adobe reader, yes, much likely. Chrome has a sandbox for pdfs as far as I'm aware, they also provide a lot of big bug bounties to people who find any remote execution bugs in Chrome. So, in conclusion, yes, chrome provides relatively more security than other software when opening PDFs.

[Danieru]

Even better would be firefox's javascript based pdf reader.

[rbanffy]

You can always open it inside a throwaway VM. I keep a couple ;-)