Import Question JSON

Current Question (ID: 20790)

Question:

$\text{A gaseous hydrocarbon upon combustion gives } 0.72 \text{ g of water and } 3.08 \text{ g of } \text{CO}_2. \text{ The empirical formula of the hydrocarbon is:}$

Options:

1. $\text{C}_6\text{H}_5$
2. $\text{C}_7\text{H}_8$
3. $\text{C}_2\text{H}_4$
4. $\text{C}_3\text{H}_4$

Solution:

$\text{Hint: The molar ratio of C and H is } 7:8.$ $\text{The general equation of combustion is as follows:}$ $\text{C}_x\text{H}_y + \left(x + \frac{y}{4}\right)\text{O}_2 \rightarrow x\text{CO}_2 + \frac{y}{2}\text{H}_2\text{O}$ $\text{The mole of hydrogen and carbon remain conserved in the reaction.}$ $\text{Calculate the mole of hydrogen and carbon in the reaction as:}$ $\text{H}_2\text{O} = \frac{0.72}{18} = 0.04 \text{ mol} = 0.08 \text{ mol }''\text{H}''$ $\text{CO}_2 = \frac{3.08}{44} = 0.07 \text{ mol} = 0.07 \text{ mol }''\text{C}''$ $x : \frac{y}{2} = 7 : 4$ $x : y = 7 : 8 \Rightarrow \text{C}_7\text{H}_8$ $\text{Hence, option second is the correct answer.}$

Import JSON File

Upload a JSON file containing LaTeX/MathJax formatted question, options, and solution.

Expected JSON Format:

{
  "question": "The mass of carbon present in 0.5 mole of $\\mathrm{K}_4[\\mathrm{Fe(CN)}_6]$ is:",
  "options": [
    {
      "id": 1,
      "text": "1.8 g"
    },
    {
      "id": 2,
      "text": "18 g"
    },
    {
      "id": 3,
      "text": "3.6 g"
    },
    {
      "id": 4,
      "text": "36 g"
    }
  ],
  "solution": "\\begin{align}\n&\\text{Hint: Mole concept}\\\\\n&1 \\text{ mole of } \\mathrm{K}_4[\\mathrm{Fe(CN)}_6] = 6 \\text{ moles of carbon atom}\\\\\n&0.5 \\text{ mole of } \\mathrm{K}_4[\\mathrm{Fe(CN)}_6] = 6 \\times 0.5 \\text{ mol} = 3 \\text{ mol}\\\\\n&1 \\text{ mol of carbon} = 12 \\text{ g}\\\\\n&3 \\text{ mol carbon} = 12 \\times 3 = 36 \\text{ g}\\\\\n&\\text{Hence, 36 g mass of carbon present in 0.5 mole of } \\mathrm{K}_4[\\mathrm{Fe(CN)}_6].\n\\end{align}",
  "correct_answer": 4
}