hii,
i was going through the filesystem explanation of linux and it was mentioned there that any root directory is always stored in inode number 2. Why sooo???

I'm no expert in these matters, but that's probably because the very first inode(s) (numbers 0 and 1) are used
to store the so-called "superblock", which holds a record of the available inodes. Inode 2 would then be the first one after that, and hence the logical one to use for the highest level directory.

maybe, but thn why superblock occupies to inode values???

I'm not sure it does. It could be that it just occupies the first one, and that the second inode is occupied by something else (for instance, a backup copy of the superblock or of some other important filesystem table).

it cud be a possibility...but still it leaves it in the middle

Inodes 0 and 1 have special and historical meanings which may or may not be valid for your filesystem. But because of this, inode 2 is always used for the root of the filesystem so that it's consistent.

Inode 0: deleted files/directories, some systems use it to point the the inodes, some don't use it at all, system dependent.
Inode 1: bad blocks, file system creation time, etc... again it's very fs dependent.

It's not for storing a backup of the superblock or anything else like that. It's just two reserved data structures which have special purposes for the file-system. What exactly is dependent on the file-system itself.

Edit: The man-page fs(5) (in FreeBSD) says the following about why they stick with the number 2 for the root.