I don't do chats anymore so I cannot make any suggestions. However, IMO, the best thing to do is to go to the play store, search for chat apps and see which one has the most downloads. then research it.
Thanks for your suggestion mate. Actually I am looking for a web based chat app. Hangouts is better but not suitiale for me. I am looking for a web based chat app. So that I can chat with lots of people at a time. However I found something from the internet "ChatWing" This has impressed me a lot. Also this supportable for iOS, iPad/iPhone and Android as well. So I would like to set up ChatWing for my website.