A metal oxide contains 60% metal . The equivalent weight of metal is

Options

A. 12
B. 60
C. 40
D. 24

Answer

To find the equivalent weight of the metal in the metal oxide that contains 60% metal, we can follow these steps:

### Step 1: Determine the percentage of oxygen in the metal oxide.
Since the metal oxide contains 60% metal, the remaining percentage must be oxygen.
\[ \text{Percentage of oxygen} = 100\% - 60\% = 40\% \]

### Step 2: Use the concept of equivalent weight.
The equivalent weight of a substance can be calculated using the formula:
\[ \text{Equivalent weight} = \frac{\text{Molecular mass}}{\text{Valence}} \]

### Step 3: Find the equivalent weight of oxygen.
The molecular mass of oxygen (O) is 16 g/mol. Oxygen typically has a valence of 2 in oxides. Therefore, we can calculate the equivalent weight of oxygen:
\[ \text{Equivalent weight of oxygen} = \frac{16}{2} = 8 \text{ g/equiv} \]

### Step 4: Set up the equation for the equivalent weight of the metal.
Let the equivalent weight of the metal be \( E_m \). We can use the percentages of metal and oxygen along with the equivalent weight of oxygen to set up the following relationship:
\[ \frac{60}{E_m} = \frac{40}{8} \]

### Step 5: Solve for the equivalent weight of the metal.
Rearranging the equation gives:
\[ \frac{60}{E_m} = 5 \quad \Rightarrow \quad E_m = \frac{60}{5} = 12 \text{ g/equiv} \]

### Conclusion:
The equivalent weight of the metal is 12 g/equiv.