Q.vinegar for spider mites
can I spray spider mites on my hibiscus with a vinegar/water solution to get rid of them?

Certified GKH Gardening Expert
You could but it would really have to be diluted in order not to hurt your hibiscus. Then it would likely not affect the spider mites though. I would instead recommend using neem oil to treat the spider mites. It is very effective on these pests and will not pose any harm to the plant or you. Here is more information: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm