The pH values of 0.1 M solution of HCl, CH3COOH, NH4Cl and CH3COONa will have the order :

Options

A. `HCl lt CH_(3)COOH lt NH_(4)Cl lt CH_(3)COONa`
B. `CH_(3)COONa lt NH_(4)Cl lt CH_(3)COOH lt HCl`
C. `NH_(4)Cl lt CH_(3)COONa lt CH_(3)COOH lt HCl`
D. All will have same of pH value

Explanation

To determine the order of pH values for a 0.1 M solution of HCl, CH3COOH, NH4Cl, and CH3COONa, we need to analyze each substance based on its properties as an acid, base, or salt.

### Step-by-Step Solution:

1. **Identify the nature of each compound:**
- **HCl**: Strong acid that completely dissociates in solution.
- **CH3COOH (Acetic Acid)**: Weak acid that partially dissociates in solution.
- **NH4Cl (Ammonium Chloride)**: Salt of a weak base (NH3) and a strong acid (HCl), which will create an acidic solution upon hydrolysis.
- **CH3COONa (Sodium Acetate)**: Salt of a weak acid (CH3COOH) and a strong base (NaOH), which will create a basic solution upon hydrolysis.

2. **Determine the pH of each solution:**
- **HCl**: Since it is a strong acid, it completely dissociates, resulting in a high concentration of H⁺ ions. The pH is calculated as:
\[ \text{pH} = -\log[H^+] = -\log[0.1] = 1 \]
- **CH3COOH**: Being a weak acid, it does not fully dissociate. The pH will be higher than that of HCl. The dissociation can be represented as:
\[ CH3COOH \rightleftharpoons H^+ + CH3COO^- \]
The pH can be estimated using the dissociation constant (Ka), but it will be higher than 1.
- **NH4Cl**: This salt will hydrolyze to produce NH4⁺ and Cl⁻. The NH4⁺ will react with water to produce H⁺ ions:
\[ NH4^+ + H2O \rightleftharpoons NH3 + H^+ \]
This results in an acidic solution, but the pH will be higher than that of HCl.
- **CH3COONa**: This salt will hydrolyze to produce CH3COO⁻ and Na⁺. The CH3COO⁻ will react with water to produce OH⁻ ions:
\[ CH3COO^- + H2O \rightleftharpoons CH3COOH + OH^- \]
This results in a basic solution, leading to a pH greater than 7.

3. **Compare the pH values:**
- HCl has the lowest pH (strongest acid).
- NH4Cl has a higher pH than HCl but lower than CH3COOH (acidic solution).
- CH3COOH has a higher pH than NH4Cl (weak acid).
- CH3COONa has the highest pH (basic solution).

4. **Establish the order of pH values:**
- The order of pH from lowest to highest is:
\[ \text{HCl} < \text{NH4Cl} < \text{CH3COOH} < \text{CH3COONa} \]

### Final Answer:
The order of pH values for the 0.1 M solutions is:
\[ \text{HCl} < \text{NH4Cl} < \text{CH3COOH} < \text{CH3COONa} \]