Amide on heating with `P_(2)O_(5)` gives

Options

A. Alkane nitrile
B. Alkyl halide
C. Amine
D. none of these

Answer

To determine what an amide produces when heated with phosphorus pentoxide (P₂O₅), we can follow these steps:

### Step 1: Understand the Reactants
- An amide has the general structure R-C(=O)-NH₂, where R is an alkyl group.
- P₂O₅ is a strong dehydrating agent, meaning it removes water (H₂O) from the reaction.

### Step 2: Mechanism of Reaction
- When an amide is treated with P₂O₅, the dehydration process begins. The nitrogen atom in the amide can donate its electrons to the carbonyl carbon (C=O) due to its lower electronegativity compared to oxygen.
- This results in the formation of a conjugated structure where the nitrogen is positively charged, and the oxygen becomes negatively charged.

### Step 3: Formation of Intermediate
- The negatively charged oxygen from the P₂O₅ can then interact with the phosphorus atom, leading to the formation of an intermediate compound. This intermediate retains the carbon-nitrogen bond and the phosphorus-oxygen bond.

### Step 4: Proton Transfer
- A proton transfer occurs where a hydrogen atom from the nitrogen is transferred to the negatively charged oxygen, stabilizing the structure.

### Step 5: Elimination of By-products
- The intermediate can undergo elimination, where a group leaves, resulting in the formation of a nitrile (R-C≡N) and a by-product that contains phosphorus and oxygen.

### Step 6: Final Product
- The final product of this reaction is an alkyl nitrile (R-C≡N), which is formed as the major product when an amide is heated with P₂O₅.

### Conclusion
- Therefore, the correct answer to the question "Amide on heating with P₂O₅ gives" is **Alkyl Nitrile**.

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