Solution with reserve acidity and alkalinity are called :-

Options

A. Isohydric solution
B. True solution
C. Normal soltion
D. Buffer solution

Answer

To solve the question regarding solutions with reserve acidity and alkalinity, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Reserve Acidity and Alkalinity**:
- Reserve acidity refers to the capacity of a solution to resist changes in pH when small amounts of acid (H⁺ ions) are added.
- Reserve alkalinity refers to the capacity of a solution to resist changes in pH when small amounts of base (OH⁻ ions) are added.

2. **Identifying the Concept**:
- The terms "reserve acidity" and "reserve alkalinity" are closely related to the concept of buffer solutions. A buffer solution is designed to maintain a stable pH when small amounts of acids or bases are introduced.

3. **Defining Buffer Capacity**:
- Buffer capacity is defined as the amount of acid or base (in gram equivalents) that must be added to a buffer solution to change its pH by one unit. This capacity is a measure of how well the buffer can maintain its pH.

4. **Examples of Buffer Solutions**:
- Common examples of buffer solutions include:
- Blood, which maintains a stable pH in the body.
- A mixture of acetic acid and sodium acetate, which can resist changes in pH.

5. **Conclusion**:
- Based on the understanding that reserve acidity and alkalinity refer to the buffer capacity of a solution, we can conclude that the answer to the question is:
- **Buffer Solution**.

### Final Answer:
The solution with reserve acidity and alkalinity is called a **Buffer Solution**.

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