Active mass of a `6%` solution of a compound is `2` then calculate
molar mass of compound.

Options

A. (A) `15`
B. (B) `30`
C. (C) `60`
D. (D) `120`

Answer

To solve the problem of calculating the molar mass of a compound from a 6% solution where the active mass (molarity) is given as 2, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Given Information**:
- We have a 6% solution of a compound.
- The active mass (molarity) of the solution is 2 mol/L.

2. **Convert Percentage to Mass**:
- A 6% solution means there are 6 grams of solute in 100 mL of solution.

3. **Convert Volume to Liters**:
- Since molarity is expressed in moles per liter, we need to convert the volume from mL to L.
- 100 mL = 0.1 L.

4. **Use the Molarity Formula**:
- Molarity (M) is defined as:
\[ M = \frac{\text{Number of moles of solute}}{\text{Volume of solution in liters}} \]
- We know the molarity (M) is 2, and the volume is 0.1 L.

5. **Calculate the Number of Moles of Solute**:
- Rearranging the molarity formula gives us:
\[ \text{Number of moles} = M \times \text{Volume} \]
- Substituting the values:
\[ \text{Number of moles} = 2 \, \text{mol/L} \times 0.1 \, \text{L} = 0.2 \, \text{moles} \]

6. **Relate Moles to Mass**:
- The number of moles is also given by the formula:
\[ \text{Number of moles} = \frac{\text{Mass of solute}}{\text{Molar mass}} \]
- Here, the mass of the solute is 6 grams.

7. **Set Up the Equation**:
- We can set up the equation:
\[ 0.2 = \frac{6}{\text{Molar mass}} \]

8. **Solve for Molar Mass**:
- Rearranging gives:
\[ \text{Molar mass} = \frac{6}{0.2} = 30 \, \text{g/mol} \]

### Final Answer:
The molar mass of the compound is **30 g/mol**.

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