Can a private ltd co give unsecured loan to another private

Yes, a private company can give unsecured loan to another private company after passing Board resolution u/s 292(1).  Inter-corporate deposits are not covered in the definition of 'deposit' u/s 58A.  Provisions of Sec.373A(3) relating to rate of interest are not applicable to private companies and hence the company can charge any rate which is reasonable.