When 400 mL of 0.2 N solution ofa weak acid is neutralized by a dilute aqueous solution of sodium hydroxide un der standard conditions, 4.4 kJ amount of heat is liberated. Therefore, the standard enthalpy of neutralization of this weak acid in kJ equiv`""^(-1)` is

Options

A. `-11`
B. `-44`
C. `-55`
D. `-22`

Answer

To find the standard enthalpy of neutralization of the weak acid in kJ per equivalent, we can follow these steps:

### Step 1: Calculate the number of equivalents of the weak acid.
The number of equivalents can be calculated using the formula:
\[ \text{Number of equivalents} = \text{Normality} \times \text{Volume in liters} \]
Given:
- Normality (N) = 0.2 N
- Volume (V) = 400 mL = 0.4 L

Substituting the values:
\[ \text{Number of equivalents} = 0.2 \, \text{N} \times 0.4 \, \text{L} = 0.08 \, \text{equivalents} \]

### Step 2: Determine the heat released per equivalent.
The total heat released during the neutralization is given as 4.4 kJ. To find the heat released per equivalent of acid, we use the formula:
\[ \text{Heat per equivalent} = \frac{\text{Total heat released}}{\text{Number of equivalents}} \]
Substituting the values:
\[ \text{Heat per equivalent} = \frac{-4.4 \, \text{kJ}}{0.08 \, \text{equivalents}} = -55 \, \text{kJ/equivalent} \]

### Step 3: Conclusion
The standard enthalpy of neutralization of the weak acid is:
\[ \Delta H_{neutralization} = -55 \, \text{kJ/equivalent} \]

### Final Answer
The standard enthalpy of neutralization of this weak acid is \(-55 \, \text{kJ/equivalent}\).

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