Can an element have variable equivalent masses ?

Answer

To determine if an element can have variable equivalent masses, we need to understand the concept of equivalent mass and how it relates to the valency of an element.

### Step-by-Step Solution:

1. **Understanding Equivalent Mass**:
Equivalent mass is defined as the mass of an element that combines with or displaces 1 mole of hydrogen or 8 grams of oxygen. The formula for calculating equivalent mass is:
\[ \text{Equivalent Mass} = \frac{\text{Molar Mass}}{n} \]
where \( n \) is the valency of the element.

2. **Identifying Valency**:
Valency is the combining power of an element, which indicates how many electrons an atom can lose, gain, or share when it forms a chemical bond. An element can exhibit different valencies depending on the chemical reaction it is involved in.

3. **Example of Iron**:
Let's consider iron (Fe) as an example. The atomic mass of iron is 56 g/mol. Iron can exhibit two different valencies:
- Valency of +2
- Valency of +3

4. **Calculating Equivalent Mass for Different Valencies**:
- For valency +2:
\[ \text{Equivalent Mass} = \frac{56}{2} = 28 \, \text{g/equiv} \]
- For valency +3:
\[ \text{Equivalent Mass} = \frac{56}{3} \approx 18.67 \, \text{g/equiv} \]

5. **Conclusion**:
Since the equivalent mass of iron changes based on its valency (28 g/equiv for +2 and approximately 18.67 g/equiv for +3), we can conclude that an element can indeed have variable equivalent masses.

### Final Answer:
Yes, an element can have variable equivalent masses.