Normally in a phone interview they are interested in hearing about your experience and details of projects that you have worked on. In my experience they save the in-depth technical questions for the face to face. But everyone is different.
If you don't know an answer then admit that you have not come across that before and maybe work with them to work out the answer, however it is a simple question that you should know based on your CV this may not go well. Best advice is to be honest and not overstate what you can do.
Also a Senior Developer will soon find out if you have just memorisd answers.