You would have to increase the btu's. The hallway will get cooler but not like the room will because it will keep filling up with warm air from the rest of the house. You Could close the door or add another unit on the other side of the house.

Im looking to buy an ac unit that can cool off my room and the hallway. Online it suggests a 6-7000 btu ac for the sq ft of the room, but doesn't include any of the hallway measurements. If I upped it to say, 8000 or so would it be able to cool both areas?