Import Question JSON

Current Question (ID: 21538)

Question:

$\text{In context with the transition elements, which of the following statements is incorrect?}$

Options:

1. $\text{In addition to the normal oxidation state, the zero oxidation state is also shown by these elements in complexes.}$
2. $\text{In the highest oxidation states, the transition metal shows basic character and forms cationic complexes.}$
3. $\text{In the highest oxidation states of the first five transition elements (Sc to Mn), all the 4s and 3d electrons are used for bonding.}$
4. $\text{Once the d}^5 \text{ configuration is exceeded, the tendency to involve all the 3d electrons in bonding decreases.}$

Solution:

$\text{(1) The first statement is correct. The d-block element shows a zero oxidation state in the complexes, like } \text{Ni(CO)}_4. \text{ This is possible because such ligands can stabilize the metal atom by back-donation of electron density, allowing the metal to retain all its valence electrons.}$ $\text{(2) The second statement is wrong because as the oxidation state increases, the acidic character increases, not the basic character. Transition metals in their highest oxidation states (e.g., Cr(VI), Mn(VII), Os(VIII)) act as Lewis acids (electron acceptors), not bases. High oxidation states (+3 to +7) typically form anionic oxo-complexes (e.g., } [\text{MnO}_4]^-, [\text{CrO}_4]^{2-} \text{) or neutral oxides (e.g., } \text{OsO}_4), \text{ not cationic complexes.}$ $\text{(3) The third statement is also correct because the first five transition elements (Sc to Mn), show a maximum oxidation state. Like Cr shows up to +6 and Mn shows up to +7. All electrons in 3d and 4s orbitals in the case of Sc to Mn take part in bonding.}$ $\text{(4) The fourth statement is correct. Once the d}^5 \text{ configuration is exceeded, the tendency to involve all the 3d electrons in bonding decreases because the pairing of electrons takes place and fewer electrons are left for bonding.}$ $\text{Hence, option 2 is the correct answer.}$

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
}