You can install a pure Linux distro on a Chromebook, but you will need to update the firmware. Search for installing GalliumOS on a Chromebook. I read about ot

You can install a pure Linux distro on a Chromebook, but you will need to update the firmware. Search for installing GalliumOS on a Chromebook. I read about other people installing Arch Linux directly on a Chromebook. (I've tried only GalliumOS.)