The `pH` of solution, containing `0.1N` HCl and `0.1N` `CH_(3)COOH(K_(a)=2xx10^(-5))` is

Options

A. 1
B. `0.7`
C. `2`
D. `1.3`

Explanation

To find the pH of a solution containing 0.1N HCl and 0.1N acetic acid (CH₃COOH), we can follow these steps:

### Step 1: Understand the Contributions to pH
HCl is a strong acid and dissociates completely in solution, while acetic acid (CH₃COOH) is a weak acid and does not dissociate completely. Therefore, the pH of the solution will primarily be determined by the HCl concentration.

### Step 2: Calculate the Contribution of HCl
Since HCl is a strong acid, its concentration of hydrogen ions [H⁺] will be equal to its normality:
\[ [H^+] = 0.1 \, \text{N} \, \text{(from HCl)} \]

### Step 3: Calculate the pH from H⁺ Concentration
The pH is calculated using the formula:
\[ \text{pH} = -\log[H^+] \]
Substituting the value of [H⁺]:
\[ \text{pH} = -\log(0.1) \]

### Step 4: Simplify the Logarithm
We can express 0.1 as \( 10^{-1} \):
\[ \text{pH} = -\log(10^{-1}) \]
Using the property of logarithms, this simplifies to:
\[ \text{pH} = 1 \]

### Step 5: Consider the Contribution from Acetic Acid
The dissociation constant \( K_a \) for acetic acid is given as \( 2 \times 10^{-5} \). However, since HCl is a strong acid and will dominate the pH, the contribution from acetic acid can be neglected.

### Final Answer
Thus, the pH of the solution is:
\[ \text{pH} = 1 \]