A compound possesses 8% sulphur by mass. The least molecular mass is

Options

A. 300
B. 400
C. 200
D. 255

Answer

To find the least molecular mass of a compound that possesses 8% sulfur by mass, we can use the formula relating percentage composition to molecular weight.

### Step-by-Step Solution:

1. **Understand the Given Information**:
- Percentage of Sulfur (S) = 8%
- Atomic weight of Sulfur (S) = 32 g/mol

2. **Set Up the Equation**:
The percentage of an element in a compound can be expressed as:
\[ \text{Percentage of Sulfur} = \left( \frac{\text{Atomic weight of Sulfur}}{\text{Molecular weight of the compound}} \right) \times 100 \]
Substituting the known values:
\[ 8 = \left( \frac{32}{M} \right) \times 100 \]
where \( M \) is the molecular weight of the compound.

3. **Rearranging the Equation**:
To isolate \( M \), we can rearrange the equation:
\[ 8M = 32 \times 100 \]
\[ 8M = 3200 \]

4. **Solving for M**:
Now, divide both sides by 8 to find \( M \):
\[ M = \frac{3200}{8} \]
\[ M = 400 \]

5. **Conclusion**:
The least molecular mass of the compound is 400 g/mol.

### Final Answer:
The least molecular mass is **400 g/mol**.