A student wrote the thermal decomposition of lead nitrate as Pb(NO₃)₂ → PbO + NO₂ + O₂ and claimed that it was balanced. Which change gives the correct balanced equation?
Answer and explanation
Correct answer: 2Pb(NO₃)₂ → 2PbO + 4NO₂ + O₂
Balancing requires equal numbers of every atom on both sides. In option A, the left side contains 2 Pb, 4 N and 12 O atoms. The right side contains 2 Pb in 2PbO, 4 N in 4NO₂, and 2 + 8 + 2 = 12 O atoms. Therefore, 2Pb(NO₃)₂ → 2PbO + 4NO₂ + O₂ is correct; the other options fail atom balance or change the product.
Frequently asked questions
What is the correct answer to this question?
2Pb(NO₃)₂ → 2PbO + 4NO₂ + O₂
Why is this the correct answer?
Balancing requires equal numbers of every atom on both sides. In option A, the left side contains 2 Pb, 4 N and 12 O atoms. The right side contains 2 Pb in 2PbO, 4 N in 4NO₂, and 2 + 8 + 2 = 12 O atoms. Therefore, 2Pb(NO₃)₂ → 2PbO + 4NO₂ + O₂ is correct; the other options fail atom balance or change the product.
Which subject and chapter does this question cover?
This is a Class 10 Science question. Chapter: Chemical Substances – Nature and Behaviour. Topic: Chemical Reactions and Equations.
