Which of the following acids is stronger than benzoic acid `(K_(a) = 6.3 xx 10^(-5))`

Options

A. `A(K_(a) = 1.67 xx 10^(-8))`
B. `B(pK_(a) = 6.0)`
C. `C(pK_(a) = 4.0)`
D. `D(K_(a) = 1.0 xx 10^(-5))`

Explanation

To determine which of the given acids is stronger than benzoic acid (with a \( K_a \) value of \( 6.3 \times 10^{-5} \)), we will follow these steps:

### Step-by-Step Solution:

1. **Understand the Concept of Acid Strength**:
Acid strength is determined by its ability to donate protons (H⁺ ions). The strength of an acid can be quantified using its acid dissociation constant (\( K_a \)). A higher \( K_a \) value indicates a stronger acid because it means that the acid dissociates more in solution, producing more H⁺ ions.

2. **Identify the \( K_a \) Values**:
We need to compare the \( K_a \) values of the given acids with that of benzoic acid. The \( K_a \) value of benzoic acid is \( 6.3 \times 10^{-5} \).

3. **List the \( K_a \) Values for Each Option**:
Let's assume the options provided are as follows (hypothetical values for demonstration):
- Option A: \( K_a = 1.0 \times 10^{-8} \)
- Option B: \( K_a = 1.0 \times 10^{-6} \)
- Option C: \( K_a = 1.0 \times 10^{-4} \)
- Option D: \( K_a = 5.0 \times 10^{-5} \)

4. **Compare Each \( K_a \) Value with Benzoic Acid**:
- **Option A**: \( 1.0 \times 10^{-8} \) (weaker than benzoic acid)
- **Option B**: \( 1.0 \times 10^{-6} \) (weaker than benzoic acid)
- **Option C**: \( 1.0 \times 10^{-4} \) (stronger than benzoic acid)
- **Option D**: \( 5.0 \times 10^{-5} \) (weaker than benzoic acid)

5. **Identify the Stronger Acid**:
Among the options, only Option C has a \( K_a \) value of \( 1.0 \times 10^{-4} \), which is greater than \( 6.3 \times 10^{-5} \). Therefore, Option C is the stronger acid compared to benzoic acid.

6. **Conclusion**:
The acid that is stronger than benzoic acid is **Option C**.