What happens when I get new Apple ID?

Do the applications that I have on my iphone now disappear or do they remain?

When you make a new Apple ID, you are basically making a new account with Apple. However, if you sign in to this new account on iTunes and connect your device, the songs, movies, etc. Will sync to your new account! Hope I helped!

Yes, if you make a new Apple ID and login with new id then your stored application on your phone will disappear.