Import Question JSON

Current Question (ID: 10957)

Question:

$\text{Nitric acid is added to sodium extract before adding silver nitrate for testing halogens because:}$

Options:

1. $\text{Nitric acid reduces sulphide}$
2. $\text{Nitric acid decomposes NaCN and Na}_2\text{S}$ (Correct)
3. $\text{Nitric acid oxidises the organic compound}$
4. $\text{Nitric acid acts as a dehydrating agent}$

Solution:

$\text{Hint: Lassaigne's test is used to detect halogens, N, P, and S}$ $\text{Step 1:}$ $\text{While testing Lassaigne's extract for the presence of halogens, it is first boiled with dilute nitric acid. This is done to decompose NaCN to HCN and Na}_2\text{S to H}_2\text{S and to expel these gases. That is, if any nitrogen and sulphur are present in the form of NaCN and Na}_2\text{S, then they are removed.}$ $\text{Step 2:}$ $\text{The chemical equations involved in the reaction are represented as:}$ $\text{NaCN} + \text{HNO}_3 \rightarrow \text{NaNO}_3 + \text{HCN}$ $\text{Na}_2\text{S} + 2\text{HNO}_3 \rightarrow 2\text{NaNO}_3 + \text{H}_2\text{S}$

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
}