Q.hybiscus leaves are turning yellow and falling off
MY HYBISCUS LEAVES ARE TURNING YELLOW AND FALLING OFF ALONG WITH THE BUDS

Certified GKH Gardening Expert
It will be hard to know what it is without seeing a photo, and having quite a bit more information on the care, the type of food and when you feed it, and all of the information that you can provide about the environment and area in which it resides.
Please provide detailed information and photos of the plant and soil around it. It could be a number of problems, and I'd like to give you the best help possible.

Yellow leaves on Hibiscus can be caused by a few different things.
This article will help you access the plant.