I purchased Lightroom 6 and I would like to try out on trial basis Lightroom Mobile, which I believe a trial is available for Lightroom CC only. so if I download Lightroom CC will my LR6 catalog be available to me or will it be another LR account? When the trial ends will the photos be available in the LR 6 catalog?
CC or stand-alone, they both use the very same catalog. That said, you're save when you change the licensing model.