Google Scholar ranks journals according to h-index while impact factor is well known as a ranking system. Both have their advantages and disadvantages. Let's discuss.
The impact factor is calculated for journals, the h index for persons. Therefore it is not possible to say which is better. See also these discussions:
When you see a high IF journal, it means the journal has higher citations per documents; however, a high h-index journal is one with higher standard peer-review process. Publishing in higher h-index journals is relatively difficult due to their low acceptance rates. Of course, please note that most of the time, higher IFs have high h-index and those with low IFs have usually low h-index but there exists exceptions! So, as a general guide, always open your eyes and look for a journal with high IF and low h-index!