Import Question JSON

Current Question (ID: 21527)

Question:

$\text{Which of the following lanthanoids do not form MO}_2 \text{ [where M is a lanthanoid metal]?}$

Options:

1. $\text{Pr}$
2. $\text{Dy}$
3. $\text{Nd}$
4. $\text{Yb}$

Solution:

$\text{Yb in } +2 \text{ oxidation state has } f^{14} \text{ configuration}$ $\text{In the lanthanoids, La(II) and Ln(III) compounds are the predominant species.}$ $\text{However, occasionally } +2 \text{ and } +4 \text{ ions in solution or in solid compounds are also obtained.}$ $\text{Pr, Nd, Tb, and Dy also exhibit a } +4 \text{ state but only in oxides, MO}_2. \text{ Yb in } +2 \text{ oxidation state has } f^{14} \text{ configuration.}$ $\text{It is a stable configuration. Hence, it will not form Yb } +4 \text{ and YbO}_2 \text{ compound did not form.}$ $\text{The electronic configuration of Pr, Dy, Nd, Tb is as follows:}$ $\text{Pr = [Xe] } 4f^3 6s^2$ $\text{Dy = [Xe] } 4f^{10} 6s^2$ $\text{Nd = [Xe] } 4f^4 6s^2$ $\text{Yb = [Xe] } 4f^{14} 6s^2$

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
}