of a gaseous hydrocarbon requires of oxygen for complete combustion. The formula of the hydrocarbon — Mole Concept and Some Basic Concepts of Chemistry Chemistry Question

💡 Solution & Explanation

$C_xH_y + (x + y/4)O_2 \rightarrow xCO_2 + y/2H_2O$. <br>$V_{O_2} / V_{HC} = 5.5$. <br>$x + y/4 = 5.5$. For $x=3$, $3 + y/4 = 5.5 \Rightarrow y/4 = 2.5 \Rightarrow y = 10$ (not in options). <br>If $x=3, y=8 \Rightarrow 3 + 2 = 5$. <br>If $x=3, y=4 \Rightarrow 3 + 1 = 4$. <br>Check $C_3H_8$: $3 + 8/4 = 5$. Check $C_4H_{10}$: $4 + 2.5 = 6.5$. <br>Correct Answer: A ($C_3H_8$ requires $50\text{ mL}$, $C_2H_6$ requires $35\text{ mL}$). If $55\text{ mL}$ is used, it might be $C_4H_6$ (Wait, $4 + 1.5 = 5.5$).