Question

A method of producing phosphine, PH₃, from elemental phosphorus, P₄, involves heating the P₄ with H₂O. An additional product is phosphoric acid. Write a balanced equation for this reaction.

a) P₄ + 6H₂O → 4PH₃ + 3H₃PO₄
b) P₄ + 4H₂O → 2PH₃ + 2H₃PO₄
c) P₄ + 5H₂O → 3PH₃ + 2H₃PO₄
d) P₄ + 2H₂O → PH₃ + H₃PO₄

Answer 1

The correct balanced chemical equation for the production of phosphine and phosphoric acid from elemental phosphorus and water is P4 + 6H2O → 4PH3 + 3H3PO4, which is option (a).

Step-by-step explanation:

The question requires us to determine the balanced chemical equation for the reaction in which elemental phosphorus, P4, is heated with H2O to produce phosphine (PH3) and phosphoric acid. Looking at the given options, we can apply the law of conservation of mass to balance the equation by ensuring that the number of each type of atom on the reactant side is the same as on the product side.

By inspecting each option given in the question:

1. P4 + 6H2O → 4PH3 + 3H3PO4 - This equation is balanced. There are four phosphorus atoms and twelve hydrogen atoms on both sides of the equation.
2. P4 + 4H2O → 2PH3 + 2H3PO4 - Unbalanced with respect to hydrogen and phosphorus atoms.
3. P4 + 5H2O → 3PH3 + 2H3PO4 - Unbalanced with respect to hydrogen and phosphorus atoms.
4. P4 + 2H2O → PH3 + H3PO4 - Unbalanced with respect to hydrogen and phosphorus atoms.

Therefore, the correct balanced equation is option (a): P4 + 6H2O → 4PH3 + 3H3PO4.