0.14 gm of an acid required 12.5 ml of 0.1 N `NaOH` for complete neuturalisation.The equivalent mass of the acid is:

Options

A. 63
B. 56
C. 45
D. 112

Explanation

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

### Step 1: Identify the given data
- Mass of the acid (m) = 0.14 g
- Volume of NaOH (V) = 12.5 mL = 12.5 × 10^-3 L (convert mL to L)
- Normality of NaOH (N) = 0.1 N

### Step 2: Calculate the milliequivalents of NaOH
The formula to calculate milliequivalents (mEq) is:
\[ \text{mEq} = \text{Volume (L)} \times \text{Normality (N)} \]
Substituting the values:
\[ \text{mEq of NaOH} = 12.5 \times 10^{-3} \, \text{L} \times 0.1 \, \text{N} = 1.25 \, \text{mEq} \]

### Step 3: Understand the neutralization reaction
In a neutralization reaction, the milliequivalents of the acid will be equal to the milliequivalents of the base (NaOH). Therefore:
\[ \text{mEq of acid} = \text{mEq of NaOH} = 1.25 \, \text{mEq} \]

### Step 4: Calculate the equivalent weight of the acid
The equivalent weight (or equivalent mass) of the acid can be calculated using the formula:
\[ \text{Equivalent weight} = \frac{\text{mass of acid}}{\text{mEq of acid}} \]
Substituting the values:
\[ \text{Equivalent weight} = \frac{0.14 \, \text{g}}{1.25 \times 10^{-3} \, \text{Eq}} = \frac{0.14 \, \text{g}}{0.00125 \, \text{Eq}} = 112 \, \text{g/Eq} \]

### Step 5: Conclusion
The equivalent mass of the acid is 112 g/Eq.