How can I hang up calls on my Alcatel android?

I was having a conversation when the phone disconnected and I can't get back to the phone call, thus cannot hang it up.

Welcome to Android Central! What do you mean the phone disconnected? How do you know the call is still connected? If there's an active call and the Phone app isn't open, then you should see a phone icon in the notification bar. Swipe down the notification panel and tap the ongoing call notification, and the Phone app should open back up to the call.

You can also use the (usually) button to the right of the home button to bring up your open apps, one of which should be the phone app with the connected call. :)