JEE Main Chemistry question
20 mL of CH₄ is burnt with 60 mL of O₂. If all measurements are made at the same P and T, what is the volume of unreacted oxygen?
Answer: (B)
Solution
CH₄ + 2O₂ → CO₂ + 2H₂O. 20 mL CH₄ requires 2 × 20 = 40 mL O₂. Unreacted O₂ = 60 − 40 = 20 mL.