Which of the following statements with regard to heating of lead nitrate powder over a flame are correct?
- Brown fumes of NO are released.
- Colourless O₂ gas is released.
- It is an example of oxidation reaction.
- It is an example of thermal decomposition used for the production of NO₂ gas.
Select the correct answer using the code given below.
1 and 2
2, 3 and 4
1, 3 and 4
2 and 4 only
Answer is Wrong!
Answer is Right!
This question was previously asked in
UPSC CDS-1 – 2023
Statement 1: Brown fumes of NO are released. Incorrect. The brown fumes are due to nitrogen dioxide (NO₂), not nitrogen monoxide (NO), which is colourless.
Statement 2: Colourless O₂ gas is released. Correct. Oxygen gas is a product of the decomposition and is colourless.
Statement 3: It is an example of oxidation reaction. Correct. While it’s a redox reaction involving both oxidation and reduction (Nitrogen is reduced from +5 to +4 in NO₂, and Oxygen is oxidized from -2 in NO₃⁻ to 0 in O₂), it is valid to say that it is *an example* of a reaction where oxidation occurs.
Statement 4: It is an example of thermal decomposition used for the production of NO₂ gas. Correct. Heating breaks down lead nitrate, and NO₂ is one of the products, making it a method for producing NO₂.
Statements 2, 3, and 4 are correct, while statement 1 is incorrect.