Admin Responsibilities for Executives-
1)House Keeping
2)Liasoning with Govt Offices.
3)Stock & Stationary
4)Office Maintenance
5)Vendors
6)Handling Events like office picnic,Annua; day celebrations,Guests
7)Hotel booking/Air-Road-Train Bookings.

Setting up of new offices/Guest Houses
9)Coordinating with Architects if any Office Interiors changes to be done.
10)Canteen Hygiene
11)Maintenance of Office cars/Booking of vehicles.
12)AMC
Apart from the above listed ones,there are lots of other works on a daily basis which you will be able to experience in a few days.An admin personnel have to be on his/her toes fron Day 1. So all the best..
Regards
Sandesh