Potassium hydroxide (KOH) is formed when Potassium forms ionic bonds with OH-ions while Potassium Oxide (K2O) is formed when potassium forms ionic bonds with the Oxide (O2-) ions. i.e. This reaction is a neutralization reaction and occurs when an acid (HCl) reacts with a base (KOH).
Experiments test the scientists' ideas.
The answer would be D. The only minerals harder than corundum is diamond.
It’s C I think and I’m not sure