The dessociation cosntants of acetic acid and propionic acid are `1.0 xx 10^(-5)` and `1.0 xx 10^(-6)` respectively. The value of `P^(K_(a))` (propionic acid) - `P^(K_(a))` (Acetic acid) is

Options

A. 10
B. `10^(-1)`
C. 1
D. `-1.0`

Answer

To solve the problem of finding the difference in pKa values between propionic acid and acetic acid, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the dissociation constants (Ka)**:
- For acetic acid (CH₃COOH), the dissociation constant, \( K_a \), is \( 1.0 \times 10^{-5} \).
- For propionic acid (C₂H₅COOH), the dissociation constant, \( K_a \), is \( 1.0 \times 10^{-6} \).

2. **Calculate the pKa values**:
- The formula for pKa is given by:
\[ pK_a = -\log(K_a) \]
- For acetic acid:
\[ pK_a \text{ (acetic acid)} = -\log(1.0 \times 10^{-5}) = 5 \]
- For propionic acid:
\[ pK_a \text{ (propionic acid)} = -\log(1.0 \times 10^{-6}) = 6 \]

3. **Find the difference in pKa values**:
- Now, we need to find the difference:
\[ pK_a \text{ (propionic acid)} - pK_a \text{ (acetic acid)} = 6 - 5 = 1 \]

### Final Answer:
The value of \( pK_a \text{ (propionic acid)} - pK_a \text{ (acetic acid)} \) is **1**.

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