Sentences 1-4 should be 'hand in' rather than 'hand it'. However, "Oh no! We had to hand it in today" where 'it' is the direct object. 'To hand something to somebody' means to give it them by literally passing it from hand to hand. 'To hand in something' is to submit. We also say 'to turn in something' or 'to turn something in'.

actually, it should be "hand in". it's a phrasal verb. it means to submit. it also can be separable, for example i will hand my homework in tomorrow.

To hand is to give and in some cases it may mean submit.. It's applicable to almost everything you would like to give... Your sentences may sound better this way: 1. I always hand my homework to you on time. 2. Do we have to hand our project to you tomorrow? 3.You never handed your homework on time. 4. When will you hand your projwct to me? 5. We have to hand it today. Is better If you would mention hand IT + homework would would redundant, so you have to ommit it since you are already mentioning homework, like what you did in the last sentence. And if you would insisting in using it, in that case you have to ommit homework...