Medium MCQ +4 / -1 PYQ · JEE Mains 2023

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

  1. A $\mathrm{C_9H_6}$
  2. B $\mathrm{C_6H_6}$
  3. C $\mathrm{C_8H_6}$ Correct answer
  4. D $\mathrm{C_9H_9}$

Solution

<p>$${C_x}{H_y} + \left( {x + {y \over 4}} \right){O_2} \to xC{O_2} + {y \over 2}{H_2}O$$</p> <p>${y \over 2} = 3$</p> <p>$y = 6$</p> <p>$x + {y \over 4} = {{19} \over 2}$</p> <p>$x = {{19} \over 2} - {3 \over 2} = 8$</p> <p>So, formula is ${C_8}{H_6}$.</p>

About this question

Subject: Chemistry · Chapter: Some Basic Concepts of Chemistry · Topic: Mole Concept

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