Q1. [1]
Consider the following chemical equation :
p Al + q H₂O ⟶ r Al₂O₃ + s H₂
To balance this chemical equation, the values of 'p', 'q', 'r' and 's' must be respectively :
- (A) 3, 2, 2, 1
- (B) 2, 3, 3, 1
- (C) 2, 3, 1, 3
- (D) 3, 1, 2, 2
Previously asked in CBSE board exam
2025 31/3/1 Q1
Generated by claude-sonnet-4-6 · 2026-06-14 10:30 · grounding rag
Model Answer
(C) 2, 3, 1, 3
Balancing: 2Al + 3H₂O → Al₂O₃ + 3H₂ (Al: 2=2, O: 3=3, H: 6=6). ✓
Explanation
Balance by hit-and-trial: start with Al₂O₃ (needs 2 Al on LHS), then balance O by putting 3H₂O, which gives 6 H atoms, requiring 3H₂ on RHS. Always verify all atoms on both sides after assigning coefficients.
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