I think it’s c but I could be wrong
Answer:
Explanation:Calcium oxide (CaO), commonly known as quicklime or burnt lime, is a widely used chemical ... Chemical formula. CaO ... Both it and a chemical derivative (calcium hydroxide, of which quicklime is the base anhydride) are important commodity ... The major use of quicklime is in the basic oxygen steelmaking (BOS) process.
Realize that pH + pOH = 14
so, 9 + pOH = 14 -> pOH = 5
pOH = -log[OH-]
5 = -log[OH-]
plug it into a calculator and you get 1.0 x 10^-5
alternatively, use [OH-] = 10^-pOH to get the same answer
[OH-] = 1.0 x 10^-5
