Molecular mass of tribasic acid is w. Its equivalent mass would be -

Options

A. `W//2`
B. `W//3`
C. W
D. `3W`

Answer

To find the equivalent mass of a tribasic acid given its molecular mass \( W \), we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of a Tribasic Acid**:
A tribasic acid is an acid that can donate three hydrogen ions (H⁺) to a base. This means that the basicity of the acid is 3.

2. **Identify the Formula for Equivalent Mass**:
The equivalent mass of an acid can be calculated using the formula:
\[ \text{Equivalent Mass} = \frac{\text{Molecular Mass}}{\text{n-factor}} \]
where the n-factor is the number of replaceable hydrogen ions.

3. **Determine the n-factor for a Tribasic Acid**:
Since the acid is tribasic, it can donate 3 hydrogen ions, so the n-factor is 3.

4. **Substitute Values into the Formula**:
Now, substituting the values into the formula:
\[ \text{Equivalent Mass} = \frac{W}{3} \]

5. **Conclusion**:
Therefore, the equivalent mass of the tribasic acid is \( \frac{W}{3} \).

### Final Answer:
The equivalent mass of the tribasic acid is \( \frac{W}{3} \).

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