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When a hydrocarbon A undergoes combustion in the presence of air, it requirs 9.5 equivalents of oxygen and produces 3 equivalents of water. What is the molecular formula of A ?

Option: 1

\mathrm{C}_9 \mathrm{H}_9


Option: 2

\mathrm{C}_8 \mathrm{H}_6


Option: 3

\mathrm{C}_9 \mathrm{H}_6


Option: 4

\mathrm{C}_6 \mathrm{H}_6


Answers (1)

best_answer

$$ \mathrm{C}_{\mathrm{x}} \mathrm{H}_{\mathrm{y}}+\left(\mathrm{x}+\frac{\mathrm{y}}{4}\right) \mathrm{O}_2 \longrightarrow \mathrm{xCO}_2+\frac{\mathrm{y}}{2} \mathrm{H}_2 \mathrm{O}
Number of equivalents of \mathrm{O}_2= Number of equivalents of \mathrm{H}_2 \mathrm{O}
Number of equivalents of \mathrm{H}_2 \mathrm{O}=\frac{\mathrm{y}}{2}=3
$$ y=6
Number of equivalents of \mathrm{O}_2=\mathrm{x}+\frac{\mathrm{y}}{4}=9.5
$$ \begin{aligned} & x+\frac{6}{4}=9.5 \\ & x=9.5-1.5=8 \\ & \mathrm{C}_{\mathrm{x}} \mathrm{H}_{\mathrm{y}}=\mathrm{C}_8 \mathrm{H}_6 \end{aligned}

Posted by

Divya Prakash Singh

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