Phosphoric acid is a triprotic acid ( K a1 = 6.9 × 10 − 3 , K a2 = 6.2 × 10 − 8 , and K a3 = 4.8 × 10 − 13 ). To find the pH of a buffer composed of H 2 PO − 4 ( aq ) and HPO 2 − 4 ( aq ) , which p K a value should be used in the Henderson–Hasselbalch equation?

Ka2 values should be used in obtaining pKa2 in the Henderson–Hasselbalch equation

Explanation:

During first dissociation from H3PO4 to H2PO4-, ka1 will be used, and from H2PO4-to HPO4-, ka2 values will be used, hence a buffer solution containing H2PO4-and HPO4-will use ka2 in obtaining pKa2 in the Henderson–Hasselbalch equation.

pie chart because it is in percents ( % )

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

if you need further assistance, let me know: )

~ trueboss72