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Current Question (ID: 18902)

Question:

$\text{When KMnO}_4 \text{ solution is added to hot oxalic acid solution, the decolorization is slow in the beginning but becomes instantaneous after some time. This is because:}$

Options:

1. $\text{Mn}^{2+} \text{ acts as auto catalyst.}$
2. $\text{CO}_2 \text{ is formed.}$
3. $\text{Reaction is exothermic.}$
4. $\text{MnO}_4^- \text{ catalyses the reaction.}$

Solution:

$\text{HINT: Mn}^{2+} \text{ acts as auto-catalyst.}$ $\text{Explanation:}$ $\text{In the reaction:}$ $2 \text{MnO}_4^- + 5 \text{C}_2\text{O}_4^{2-} + 16 \text{H}^+ \rightarrow 2 \text{Mn}^{2+} + 8 \text{H}_2\text{O} + 10 \text{CO}_2$ $\text{In the starting reaction is slow because of the conversion of MnO}_4^- \text{ to Mn}^{2+}$ $\text{, but when Mn}^{2+} \text{ forms then it acts as auto-catalyst which increases the rate of reaction.}$ $\text{Thus, conversion becomes fast after some time.}$

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
}