Import Question JSON

Current Question (ID: 18886)

Question:

$\text{The incorrect statement among the following is:}$

Options:

1. $\text{There is a decrease in the radii of the atoms or ions as one proceeds from La to Lu.}$
2. $\text{Lanthanoid contraction is the accumulation of successive shrinkages.}$
3. $\text{As a result of lanthanoid contraction, the properties of the 4d series of the transition elements have no similarities with the 5d series of elements.}$
4. $\text{The shielding power of 4f electrons is quite weak.}$

Solution:

$\text{HINT: Shielding of 4f orbitals is poor.}$ $\text{Explanation:}$ $\text{STEP 1:}$ $\text{Lanthanoid contraction, also called lanthanide contraction, in chemistry, the steady decrease in the size of the atoms and ions of the rare earth elements with increasing atomic number from lanthanum (atomic number 57) through lutetium (atomic number 71).}$ $\text{STEP 2:}$ $\text{The effect results from poor shielding of nuclear charge (nuclear attractive force on electrons) by 4f electrons; the 6s electrons are drawn towards the nucleus, thus resulting in a smaller atomic radius.}$ $\text{STEP 3:}$ $\text{Due to the Lanthanide contraction, properties of 4d and 5d series are quite similar as their atomic radii are quite similar. So the statement in option (3) is incorrect.}$

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
}