Q.Why are my Hibiscus leaves turning yellow?
I was just given a Hibiscus and I repotted it into a bigger container. Every other day I am finding leaves yellowing and I don’t know if I am doing something wrong. The plant sits in full sun from mid morning through mid afternoon.
Here's an article that proposes several possible answers for your problem: https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/answers-to-what-causes-hibiscus-leaves-turning-yellow.htm
When you say you repotted it into a bigger container, there's a possibility that the new container is too big. When up-potting plants, you should always go just one size up, i.e. 6" - 8", 8" - 10", etc. Planting into a pot that's too large generally results in the soil, and consequently the roots, staying too wet.