mint@mint ~ $ sudo mount /dev/sda5 /mnt
mount: /dev/sda5 already mounted or /mnt busy
mount: according to mtab, /dev/sda5 is already mounted on /mnt
****So this means its mounted because I already passed this command. Then lets proceed

mint@mint ~ $ sudo grub-install --root-directory=/mnt/ /dev/sda5
grub-probe: error: cannot find a device for /boot (is /dev mounted?).
/usr/sbin/grub-setup: warn: Attempting to install GRUB to a partitionless disk or to a partition.  This is a BAD idea..
/usr/sbin/grub-setup: warn: Embedding is not possible.  GRUB can only be installed in this setup by using blocklists.  However, blocklists are UNRELIABLE and their use is discouraged..
/usr/sbin/grub-setup: error: will not proceed with blocklists.
mint@mint ~ $ 

view gparted http://i.imgur.com/nPc6M.png