Practice question

Given: In the Dumas method, 0.5 g of a compound gave 112 mL of N₂ at STP. What is the percentage of nitrogen? (Atomic mass: N = 14) These values define the system as per NCERT data. Formula: Mass of N₂ = 28 × 112/22400 = 0.14 g. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Mass of N = 0.14 g. Percentage = 0.14 × 100/0.5 = 28% . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.