A and B are two elements of period 3. A is metal and B is non-metal. They form compound C which is tetra Atomic. What is the Compound C ??

it should be all of them because it asks if you included all of those in your answer

explanation:

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.