Can I mount /dev/sda2 in /home itself?
Yes you can. If you mount it at /home
all the files that are currently in /home
will become disappear until you unmount it.
As stress_junkie said, you could mount it at /home/extraspace
(or anywhere else for that matter) and then just use the extra space.
But if /dev/sda1
are adjacent to each other on your disk layout, you could boot from a live CD and then use gparted
to "grow" sda1 into the space allocated to sda2. This way you get to keep your files, but end up with more space to play with. Note this must
be done from a live CD when the partitions sda1 and sda2 are unmounted.
As usual, there are many possible solutions to your problem. None if them is necessarily "right".