What is the action of conc. Nitric acid on,

• a) Zinc metal
• b) P₄ - molecule
• c) S₈ - molecule?

The action of concentrated nitric acid on different substances varies significantly due to its strong oxidizing properties. Here’s how it interacts with zinc, phosphorus, and sulfur molecules:

Effect on Zinc Metal

When concentrated nitric acid reacts with zinc metal, it produces zinc nitrate, nitrogen dioxide, and water. The reaction can be summarized as follows:

• Reaction: Zn + 4HNO₃ → Zn(NO₃)₂ + 2NO₂ + 2H₂O
• Observation: Brown fumes of nitrogen dioxide are released.

Interaction with P₄ Molecule

In the case of phosphorus (P₄), concentrated nitric acid oxidizes it to phosphoric acid. The reaction is more complex and can produce various nitrogen oxides as byproducts:

• Reaction: P₄ + 10HNO₃ → 4H₃PO₄ + 10NO₂ + 2H₂O
• Observation: Brown fumes and a colorless solution of phosphoric acid are formed.

Behavior with S₈ Molecule

When sulfur (S₈) reacts with concentrated nitric acid, it is oxidized to sulfuric acid. The reaction can be represented as:

• Reaction: S₈ + 12HNO₃ → 8H₂SO₄ + 12NO₂ + 4H₂O
• Observation: Similar to the previous reactions, brown fumes of nitrogen dioxide are produced.

In summary, concentrated nitric acid acts as a powerful oxidizing agent, leading to the formation of various acids and nitrogen oxides when reacting with these substances.