We can hide us by showing offline status to the certain friends in Facebook chat. It is very easy to do as you just you have to follow some simple steps but most of the persons don't know about that so here is the step to hide yourself in Facebook chat.

Here are the steps :
1. Login to your Facebook Account and click and expand the chat menu.
2. From the chat menu click on Friend Lists (at top) and create a new list just type your list name and press enter.
3. Say, you have created Block List, now you will see Block List in your Facebook chat option.
4. Now move your mouse cursor to your Block List you will see edit option beside Block List.
5. Click on edit and immediately a pop up window will come up.
6. Now select the friends whom to show you are offline.
7. Done Selecting friends? Now click on Save List.
8. Now your selected friend automatically moved from chat list to Block List but by default your Block List will be visible and your friends of your Block List will see you online.
9. We need to show offline now. Hence if you want to show offline status to your Block List's friends, just go to Block List and you will see at the right side Go Offline click on it as shown in the below screenshot.