Which of the following base is weakest ?

Options

A. `NH_(4)OH :K_(b)=1.6xx10^(-6)`
B. `C_(6)H_(5)NH_(2), K_(b)=3.8xx10^(10)`
C. `C_(2)H_(5)NH_(2), K_(b)=5.6xx10^(-4)`
D. `C_(9)H_(7)N , K_(b)=6.3xx10^(-10)`

Explanation

To determine which of the given bases is the weakest, we need to analyze their base dissociation constants (Kb values). The strength of a base is inversely related to its Kb value; that is, the lower the Kb value, the weaker the base.

### Step-by-Step Solution:

1. **Identify the Kb values**: We are given several bases along with their Kb values. Let's list them:
- Base A: Kb = 1.6 × 10^(-6)
- Base B: Kb = 10^(-10)
- Base C: Kb = 10^(-4)
- Base D: Kb = 10^(10)

2. **Compare the Kb values**: The next step is to compare the Kb values. The base with the lowest Kb value will be the weakest base.
- Kb values in order from lowest to highest:
- Base B: 10^(-10)
- Base A: 1.6 × 10^(-6)
- Base C: 10^(-4)
- Base D: 10^(10)

3. **Determine the weakest base**: From the comparison, we can see that Base B has the lowest Kb value (10^(-10)). This indicates that it has the least tendency to ionize in solution, making it the weakest base.

4. **Conclusion**: Therefore, the weakest base among the given options is Base B.

### Final Answer:
The weakest base is Base B (Kb = 10^(-10)).

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