I don't have a 2i2 or iPad but it looks like you should be able to do it, though you may need an adaptor cable and a powered hub. I found these instructions on the Focusrite website:
There's video on that page showing how to connect a bus-powered Scarlett to an iPad via a powered hub, which I think would apply to the 2i2.
Note: On that same page it says "If you have a Scarlett 3rd Gen interface, please make sure you update the firmware on your Scarlett first, before connecting it to an iPad". The link takes you to:
Here are some other related support pages..