<span>Cations mix with anions, so you know NH4+ won't mix with K+ and SO4(2-) won't miix with F-. For the reason that NH4+ and F- together have single charges, they'll mix in a 1:1 ratio, NH4F. There's two charges on SO4(2-), so it'll need two K+ to mix with, K2SO4.</span>
Answer: I just took the test. The answer is D! (A single replacement reaction takes place because sodium is more reactive than hydrogen.)
Answer: the theory that all matter us made up of tiny invisible particles. Hope that help you out :)
Explanation: