Phosphoric acid (H3PO4) is an important industrial chemical used in fertilizers, detergents, and in the food industry. It is produced by two different methods. In the electric furnace method, elemental phosphorus (P4) is burned in air to form P4O10, which is then reacted with water to give H3PO4. In the wet process, the mineral phosphate rock [Ca5(PO4)3F] is reacted with sulfuric acid to give H3PO4 (and HF and CaSO4). (a) Write the balanced equations for the electric furnace method. Include the phase abbreviations.

P₄(s) + 5 O₂(g) ⇒ P₄O₁₀(s)

P₄O₁₀(s) + 6 H₂O(l) ⇒ 4 H₃PO₄(aq)

P₄(s) + 5 O₂(g) + 6 H₂O(l) ⇒ 4 H₃PO₄(aq)

Explanation:

The electric furnace method for the synthesis of phosphoric acid has 2 steps. In the first step, elemental phosphorus (P₄) is burned in air to form P₄O₁₀. The balanced reaction is:

P₄(s) + 5 O₂(g) ⇒ P₄O₁₀(s)

In the second step, P₄O₁₀ reacts with water to give phosphoric acid.

P₄O₁₀(s) + 6 H₂O(l) ⇒ 4 H₃PO₄(aq)

If we add both steps, we get the global reaction.

P₄(s) + 5 O₂(g) + 6 H₂O(l) ⇒ 4 H₃PO₄(aq)

a polar bond is formed when electrons are shared unevenly between atoms