I could read this question two ways, but the answer to both is 'yes'.
If you mean can you purchase, install and use the software for your federal but not access the state; yes. Simply don't download it but either way it is free if you decide you want to use it.
If you mean can you e-file your federal (free) without paying for and e-filing your state; yes. When you go through the file process, it will give you the option to e-file federal only.
Hope this helps!