Any buffer solution can be used as a buffer upto two `pH` units only.

Explanation

To determine whether the statement "Any buffer solution can be used as a buffer up to two pH units only" is true or false, we can analyze the concept of buffer capacity and its effective range.

### Step-by-Step Solution:

1. **Understanding Buffer Solutions**:
- A buffer solution is a solution that resists changes in pH upon the addition of small amounts of acid or base. There are two types of buffers: acidic buffers and basic buffers.

2. **Acidic Buffer Capacity**:
- For an acidic buffer, the pH is effective around its pKa value. The buffer action is most effective within a range of ±1 pH unit from the pKa.
- Therefore, if the pKa is known, the effective pH range of the acidic buffer can be expressed as:
\[ \text{Effective pH range} = \text{pKa} - 1 \text{ to } \text{pKa} + 1 \]
- This gives a total range of 2 pH units.

3. **Basic Buffer Capacity**:
- For a basic buffer, the pH can be related to its pKb. The relationship between pH and pKb is given by:
\[ \text{pH} = 14 - \text{pKb} \]
- Similar to acidic buffers, the effective range for basic buffers is also ±1 pH unit from the pKb.
- Thus, the effective pH range can be expressed as:
\[ \text{Effective pH range} = \text{pKb} - 1 \text{ to } \text{pKb} + 1 \]
- This also results in a total range of 2 pH units.

4. **Conclusion**:
- Since both acidic and basic buffers can effectively maintain their pH within a range of 2 units (±1 unit from their respective pKa or pKb), we can conclude that the statement is true.
- Therefore, the statement "Any buffer solution can be used as a buffer up to two pH units only" is **true**.