Answer to Question #67852 in General Chemistry for Allan Mwashumbe

Question

15 cm3 of 0.2 mole solution hydroxide react with 10cm3 of 0.15 mole of phosphoric acid H3PO4. Find the formula of the salt formed?

Answer 1

Number of moles of acid and hydroxide equal:
n(H3PO4) = C·V = 0.15·0.01 = 0.0015 (moles)
n(Me(OH)x) = C·V = 0.2·0.015 = 0.003 (moles)
Thus, n(H3PO4): n(Me(OH)x) = 1:2
The balanced chemical equation is:
2 Me(OH)x + H3PO4 → Me2HPO4 + 2H2O
So the metal has a valence I, and general formula of hydroxide is MeOH.
So the formula of formed salt is Me2HPO4.

Answer: Me2HPO4.