/dev/hda & /dev/hda1 are not directories. They are "block special files" (google that term for more info) which represent a hardware device. /dev/hda is the name of the whole disk and /dev/hda1 , /dev/hda2, etc are the partitions on that disk.
What you need to do to access those partitions is mount them (don't mount /dev/hda) into a directory and then use cd to go to that directory.
First check to see if the partition you want is already mounted.
Is the partition listed in the output? If so, it's already mounted, and the directory it lists on the right is the one you cd to.
If it's NOT listed, then you need to mount it, so first create a directory to mount the partition to:
Then mount the partition to the newly created directory:
mount /dev/hda1 /mnt/drivec
Then cd into that directory:
/mnt/drivec will contain the contents of the partition /dev/hda1 now.
Hope this helps,