NTA Abhyas JEE Main2020Chemistryp Block Elements (Group 15, 16, 17 & 18)Practice
Upon long standing, concentrated H N O 3
Options
- Aremains colourless, but gives out N O
- Bturns yellow brown due to formation of N O 2
- Cturns yellow brown due to the formation of N 2 O 4
- Dremains colourless, but gives N 2 O
Correct answer
B. turns yellow brown due to formation of N O 2
Step-by-step solution
When nitric acid is left for long standing, its color changes due to decomposition reaction. The reaction in which one reactant yields two or more products, it is called a decomposition reaction. Due to decomposition, concentrated nitric acid ( H N O 3 ) gets broken down to nitrogen dioxide, oxygen, and water. Due to the formation of nitrogen dioxide, it turns yellow-brown. The chemical reaction involved in the reaction is as follows: 4   HNO 3 → 4   NO 2   +   O 2   +