Import Question JSON

Current Question (ID: 18865)

Question:

$\text{The element that has a maximum composition in Mischmetal and is used in the gas lighters is:}$

Options:

1. $\text{Ce}$
2. $\text{Fe}$
3. $\text{Sm}$
4. $\text{La}$

Solution:

$\text{HINT: It is an alloy of La, Ce and Fe.}$ $\text{Explanation:}$ $\text{A well known alloy is mischmetall which consists of a lanthanoid metal (~ 95\%) and iron (~ 5\%) and traces of S, C, Ca and Al.}$ $\text{A good deal of mischmetall is used in Mg-based alloy to produce bullets, shell and lighter flint.}$ $\text{The percentage metal is as follows:}$ $\text{Misch metal: alloy consisting of about 50 percent cerium, 25 percent lanthanum, 15 percent neodymium, and 10 percent other rare-earth metals and iron.}$

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
}