What happens when phosphoric acid is heated ?

Answer

When phosphoric acid (H₃PO₄) is heated, it undergoes a dehydration reaction to form pyrophosphoric acid (H₄P₂O₇) and water (H₂O). Here’s a step-by-step breakdown of the process:

### Step 1: Identify the compound
- The compound we are dealing with is phosphoric acid, which has the chemical formula H₃PO₄.

### Step 2: Heating the compound
- When phosphoric acid is heated to a temperature of around 300 degrees Celsius, it begins to decompose.

### Step 3: Reaction products
- The heating of phosphoric acid leads to the formation of pyrophosphoric acid (H₄P₂O₇) and water (H₂O). The balanced reaction can be written as:
\[ 2 \, \text{H}_3\text{PO}_4 \, \text{(s)} \rightarrow \text{H}_4\text{P}_2\text{O}_7 \, \text{(s)} + \text{H}_2\text{O} \, \text{(g)} \]

### Step 4: Conclusion
- Therefore, when phosphoric acid is heated, it produces pyrophosphoric acid and water.

### Summary of the Reaction:
- **Reactants**: 2 H₃PO₄ (phosphoric acid)
- **Products**: H₄P₂O₇ (pyrophosphoric acid) + H₂O (water)

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