JEE MainChemistryp Block Elements (Group 13 & 14)
When lead(II) nitrate is heated, a brown gas A is evolved. Upon cooling, gas A dimerises to form a colourless solid B. Compound B reacts with water to produce a mixture of two oxoacids, C and D. The sum of the oxidation states of the central nitrogen atom in oxoacids C and D is
Options
- A10
- B8
- C6
- D7
Correct answer
B. 8
Step-by-step solution
Thermal decomposition of lead(II) nitrate produces nitrogen dioxide ( NO ₂ ), which is a brown gas. 2 Pb ( NO ₃)₂ 2 PbO + 4 NO ₂ + O ₂ Thus, gas A is NO ₂ . Upon cooling, NO ₂ dimerises to form dinitrogen tetroxide ( N ₂ O ₄ ), a colourless solid. 2 NO ₂ N ₂ O ₄ Compound B is N ₂ O ₄ . It is a mixed anhydride of nitrous acid ( HNO ₂ ) and nitric acid ( HNO ₃ ). It reacts with water to form a mixture of these two oxoacids. N ₂ O ₄ + H ₂ O HNO ₂ + HNO ₃ The oxoacids C and D are HNO ₂ and HNO ₃ . Let the oxidation sta