Express your answer as a chemical equation. Identify all of the phases in your answer.

H3PO + Sr(OH)2=

You need to work on this. I know of no H3PO.

To express the answer as a chemical equation, we need to balance it and indicate the phases of the substances involved.

The balanced chemical equation for the reaction between H3PO and Sr(OH)2 is:
2 H3PO4 + 3 Sr(OH)2 → 6 H2O + Sr3(PO4)2

In this equation, the phases of the substances can be indicated as follows:

2 H3PO4 (aq) + 3 Sr(OH)2 (aq) → 6 H2O (l) + Sr3(PO4)2 (s)

- "aq" represents aqueous, which means the substance is dissolved in water.
- "l" represents liquid, in this case referring to water.
- "s" represents a solid. In this equation, Sr3(PO4)2 is formed as a solid precipitate.