Oxidizer vs Non-Metals
Watch carbon and sulfur get oxidized
What this lesson covers
Why it matters
Concentrated nitric acid is so aggressive it strips electrons from non-metals like carbon and sulfur. Watch as it forces them into oxygen-rich products such as oxides and oxyacids while releasing a cloud of toxic brown gas.
The idea in plain words
Analyze the redox process: Sulfur loses electrons (oxidized) while Nitrogen gains electrons (reduced to NO₂).
Predict first
When sulfur reacts with concentrated nitric acid, what happens to the sulfur?
Nitric acid acts as an oxidizing agent, pulling electrons from sulfur to form sulfuric acid.
- It gets reduced to hydrogen sulfide gas
- It is oxidized to sulfuric acid — correct
- It dissolves physically without changing chemically
What you do
Add sulfur or carbon to the concentrated acid. Observe the effervescence and the color of the gas evolved.
Check yourself
What is the visible sign that a reaction is occurring in both cases?
Both reactions produce NO₂ gas, which appears as reddish-brown fumes, along with vigorous bubbling.
In the reaction C + 4HNO₃ → CO₂ + 2H₂O + 4NO₂, what role does carbon play?
Carbon is oxidized to CO₂, meaning it donates electrons and acts as the reducing agent.
How can you confirm the gas produced when carbon reacts with HNO₃?
The carbon reaction produces CO₂, which is identified by turning limewater milky.
- Formation of a white precipitate
- Effervescence and reddish-brown fumes — correct
- The solution turns blue
- Oxidizing agent
- Reducing agent — correct
- Catalyst
- Acid
- It relights a glowing splint
- It turns limewater milky — correct
- It burns with a pop sound