JEE Main202621 January 2026Morning ShiftChemistrySome Basic Concepts of ChemistryActual
80 mL of a hydrocarbon on mixing with 264 mL of oxygen in a closed U-tube undergoes complete combustion. The residual gases after cooling to 273 K occupy 224 mL. When the system is treated with KOH solution, the volume decreases to 64 mL. The formula of the hydrocarbon is :
Options
- AC ₂ H ₂
- BC ₂ H ₄
- CC ₂ H ₆
- DC ₄ H ₁₀
Correct answer
A. C ₂ H ₂
Step-by-step solution
KOH absorbs CO₂ . Volume of CO₂ produced = 224 - 64 = 160 mL Unreacted O₂ = 64 mL, so O₂ consumed = 264 - 64 = 200 mL For hydrocarbon C_xH_y : CO₂ Hydrocarbon = 160 80 = 2 x = 2 O₂ consumed per mole = x + y 4 = 200 80 = 2.5 2 + y 4 = 2.5 y = 2 Hydrocarbon is C₂H₂