Equivalent mass of a metal is 12 g `"mol"^(-1)`. Hence,
equivalent mass of its oxide is

Options

A. 24
B. 28
C. 20
D. 34

Answer

To find the equivalent mass of the metal oxide, we can follow these steps:

### Step 1: Identify the equivalent mass of the metal
The equivalent mass of the metal is given as 12 g/mol.

### Step 2: Calculate the equivalent mass of oxygen
The equivalent mass of an element can be calculated using the formula:

\[ \text{Equivalent mass} = \frac{\text{Molar mass}}{\text{Valency}} \]

For oxygen, the molar mass is 16 g/mol and its valency is 2 (since it typically forms O²⁻ ions).

\[ \text{Equivalent mass of oxygen} = \frac{16 \, \text{g/mol}}{2} = 8 \, \text{g/mol} \]

### Step 3: Calculate the equivalent mass of the metal oxide
The equivalent mass of the metal oxide can be calculated by adding the equivalent mass of the metal and the equivalent mass of oxygen:

\[ \text{Equivalent mass of metal oxide} = \text{Equivalent mass of metal} + \text{Equivalent mass of oxygen} \]

Substituting the values we have:

\[ \text{Equivalent mass of metal oxide} = 12 \, \text{g/mol} + 8 \, \text{g/mol} = 20 \, \text{g/mol} \]

### Conclusion
The equivalent mass of the metal oxide is 20 g/mol.

### Final Answer
The equivalent mass of the oxide is **20 g/mol** (Option C).

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