Verified Solution • 2025–26 Session moderate

QJEEM23Chf517: JEE Main 2023 Chemistry - Class 11 JEEM23Chf517 Solution: When a hydrocarbon A undergoes complete combustion it requires…

When a hydrocarbon A undergoes complete combustion it requires 11 equivalents of oxygen and produces 4 equivalents of water. What is the molecular formula of AA ?

Multiple Choice Options

  • A C9H8\mathrm{C}_{9} \mathrm{H}_{8}
  • B C5H8\mathrm{C}_{5} \mathrm{H}_{8}
  • C C11H4\mathrm{C}_{11} \mathrm{H}_{4}
  • D C11H8\mathrm{C}_{11} \mathrm{H}_{8}

Step-by-Step Verified Solution

amp;CxHy+(x+y4)O2→xCO2+y2H2Oamp;y2=4⇒y=8amp;x+84=11amp;⇒x=9amp;∴ Hydrocarbon will be =C9H8\begin{aligned}& \mathrm{C}_{\mathrm{x}} \mathrm{H}_{\mathrm{y}}+\left(\mathrm{x}+\frac{\mathrm{y}}{4}\right) \mathrm{O}_2 \rightarrow \mathrm{xCO}_2+\frac{\mathrm{y}}{2} \mathrm{H}_2 \mathrm{O} \\\\& \frac{\mathrm{y}}{2}=4 \Rightarrow \mathrm{y}=8 \\\\& \mathrm{x}+\frac{8}{4}=11 \\\\& \Rightarrow \mathrm{x}=9 \\\\& \therefore \text { Hydrocarbon will be }=\mathrm{C}_9 \mathrm{H}_8\end{aligned}

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