The term "hollow" and its opposite, "solid", refer to complete objects, like a rock, an egg, a wall, etc. The term "empty" and its opposite, "full", refer to containers, like a glass, a basket, etc., that hold other things, like water, apples, paint, etc. So you could have a hollow egg, which means it's a shell with no inside. And then you can have an empty basket, which means it doesn't contain any objects.

"Empty" is used as the opposite of "Full". For example, if you have no gas in your gas tank, you would say that it was empty. "Hollow" is a special case of this, where something is not solid and has space inside, like a rotted tree stump - you expect it to be solid, but instead all that is left is the outside and there is nothing inside, so you say that it is "hollow". You could still say that the stump is empty inside, but hollow has a more specific connotation. When in doubt, "Empty" would probably be the preferred term if you don't know what to say.