Three bases `XOH,YOH & ZOH` has `pK_(b)` values `2,3, & 4` reespectively the strongest conjugate acid is `:`

Options

A. `XOH_(2)^(+)`
B. `YOH_(2)^(+)`
C. `ZOH_(2)^(+)`
D. All same

Explanation

To determine the strongest conjugate acid among the bases \(XOH\), \(YOH\), and \(ZOH\) with given \(pK_b\) values of 2, 3, and 4 respectively, we can follow these steps:

### Step 1: Understand the Relationship Between \(pK_b\) and Basic Strength
The \(pK_b\) value indicates the strength of a base; lower \(pK_b\) values correspond to stronger bases. This is because \(pK_b\) is a measure of the base's tendency to accept protons (H\(^+\)).

### Step 2: Identify the Strength of Each Base
- For \(XOH\), \(pK_b = 2\)
- For \(YOH\), \(pK_b = 3\)
- For \(ZOH\), \(pK_b = 4\)

Since \(XOH\) has the lowest \(pK_b\), it is the strongest base. Conversely, \(ZOH\) has the highest \(pK_b\), making it the weakest base.

### Step 3: Determine the Conjugate Acids
The conjugate acid of a base is formed when the base accepts a proton (H\(^+\)). The weaker the base, the stronger its conjugate acid will be. Therefore:
- The conjugate acid of \(XOH\) is \(XOH_2^+\)
- The conjugate acid of \(YOH\) is \(YOH_2^+\)
- The conjugate acid of \(ZOH\) is \(ZOH_2^+\)

### Step 4: Identify the Strongest Conjugate Acid
Since \(ZOH\) is the weakest base, it will have the strongest conjugate acid. Therefore, \(ZOH_2^+\) is the strongest conjugate acid.

### Conclusion
The strongest conjugate acid is \(ZOH_2^+\).