Import Question JSON

Current Question (ID: 17987)

Question:

$\text{The appearance of colour in solid alkali metal halides is generally due to:}$

Options:

1. $\text{F-centres.}$
2. $\text{Schottky defect.}$
3. $\text{Frenkel defect.}$
4. $\text{Interstitial positions.}$

Solution:

$\text{HINT: Metal excess defect due to anionic vacancies.}$ $\text{Explanation:}$ $\text{Alkali halides like NaCl and KCl are coloured because of metal excess defects due to anionic vacancies. In the case of alkyl halide crystals, the chloride ion is replaced by free electrons.}$ $\text{As a result, the crystal now has an excess of the cation. The anionic sites occupied by unpaired electrons are called F-centres (from the German word Farbzenzenter for colour centre).}$

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
}