Import Question JSON

Current Question (ID: 7428)

Question:

The density of a 2 M aqueous solution of $\text{NaOH}$ is 1.28 g/$cm^3$. The molality of the solution is:\n[molecular mass of $\text{NaOH} = 40 \text{ gmol}^{-1}$]

Options:

1. 1.20 m
2. 1.56 m
3. 1.67 m
4. 1.32 m

Solution:

\text{Hint: density}, \rho = \frac{m}{V}\n\n\text{Explanation:}\n\n\text{Step 1: Moles of } \text{NaOH} = 2 \text{ mol}\n\n\text{Mass of } \text{NaOH} = V \times d = 1000 \times 1.28\n\n\text{Mass of } \text{NaOH} = 1280\n\n\text{Also, weight}(\text{H}_2\text{O}) = 1280 - 80 = 1200 \text{ g} = 1.2 \text{ kg}\n\n\text{Step 2: Molality} = m = \frac{\text{moles of solute}}{\text{kg of solvent}}\n\n\text{Molality} = m = \frac{2}{1.2} = 1.67 \text{ m}\n\n\text{Thus, option 3 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
}