The lowest value of heat of neutralization is obtained for

Options

A. `HCl+NaOH`
B. `CH_(3)COOH+NH_(4)OH`
C. `NH_(4)OH+HCl`
D. `NaOH+CH_(3)COOH`

Explanation

To determine the lowest value of heat of neutralization, we need to understand the concept of heat of neutralization and how it varies with different types of acids and bases.

### Step-by-Step Solution:

1. **Definition of Heat of Neutralization**:
- Heat of neutralization is defined as the amount of heat released when one equivalent of an acid reacts with one equivalent of a base to form water and a salt.

2. **Types of Acids and Bases**:
- There are two main categories of acids and bases: strong and weak.
- Strong acids (like HCl, H2SO4) and strong bases (like NaOH, KOH) completely dissociate in water.
- Weak acids (like CH3COOH) and weak bases (like NH4OH) do not completely dissociate.

3. **Heat of Neutralization Values**:
- The heat of neutralization for strong acid and strong base reactions is typically around -57.1 kJ/mol (or -13.7 kcal/mol).
- For weak acid and strong base or strong acid and weak base, the heat of neutralization is lower than that of strong acid-strong base reactions because additional energy is required to ionize the weak acid or weak base.

4. **Lowest Value of Heat of Neutralization**:
- The lowest value of heat of neutralization occurs when a weak acid reacts with a weak base.
- This is because the reaction does not go to completion, and the energy change is less than that of strong acid-strong base reactions.

5. **Conclusion**:
- Therefore, the lowest value of heat of neutralization is obtained for the reaction between a weak acid and a weak base.

### Final Answer:
The lowest value of heat of neutralization is obtained for the reaction between a weak acid and a weak base.

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