Q1. [1] § 1.1.1 Writing a Chemical Equation § 1.1.2 Balanced Chemical Equations
In order to balance the following chemical equation, the values of the coefficients x and y respectively are :
x Pb(NO₃)₂ → 2 PbO + y NO₂ + O₂
- (a) 2, 4
- (b) 2, 2
- (c) 2, 3
- (d) 4, 2
Previously asked in CBSE board exam
2023 31/2/1 Q3
Generated by claude-sonnet-4-6 · 2026-06-14 10:30 · grounding rag
Model Answer
(a) 2, 4
Balanced equation: $2\ \text{Pb(NO}_3)_2 \rightarrow 2\ \text{PbO} + 4\ \text{NO}_2 + \text{O}_2$. So x = 2 and y = 4.
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Explanation
Check atom balance: with x = 2, y = 4 — Pb: 2 = 2 ✓; N: 4 = 4 ✓; O: 12 = 2+8+2 = 12 ✓. The law of conservation of mass (equal atoms on both sides) confirms option (a).
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