Can you tell me if i could use baking powder instead of soda to eliminate vaginal odor?

It will be messy: Baking powder contains baking soda and cream of tartar, which is a very fine powder. So it will make a kind of goo that might help a little but also might make things worse. Better to find the cause of the odor (very often it is a buildup of the wrong kind of bacteria or yeast in the vagina), especially if there is a discharge, and to treat the cause specifically. Get it checked at any clinic.