We mix equal volume of two aqueous solution.Match the following :
`{:("Column-I","Column-II"),((A)"0.2 M KOH+ 0.5 M HCOOH", (p)0.7),((B)0.1 M NaCl+0.1 M NaNO_3,(q)between 1 "to "7),((C )0.1 M NH_4Cl+0.1 M NaOH,(r)7),((D)0.5 M HCl+0.1 M NH_4OH,(s)"greater than" 7),([log_10 2=0.3],(t)"less than 7"):}`

Explanation

To solve the problem of matching the mixtures in Column-I with their corresponding pH values in Column-II, we will analyze each mixture step by step.

### Step 1: Analyze the first mixture (A)
**Mixture:** 0.2 M KOH + 0.5 M HCOOH

1. **Identify the components:**
- KOH is a strong base.
- HCOOH (formic acid) is a weak acid.

2. **Calculate the effective concentration of H⁺ ions:**
- Normality of KOH = 0.2 N (since n-factor = 1).
- Normality of HCOOH = 0.5 N (since n-factor = 1).
- Since both solutions are mixed in equal volumes, we can use the formula:
\[ [H^+] = \frac{N_1V_1 - N_2V_2}{V_1 + V_2} \]
- Here, \(N_1 = 0.2\), \(N_2 = 0.5\), and \(V_1 = V_2 = V\):
\[ [H^+] = \frac{0.2V - 0.5V}{2V} = \frac{-0.3V}{2V} = -0.15 \text{ (which indicates a basic solution)} \]

3. **Calculate pH:**
- Since the concentration of H⁺ ions is negative, we can conclude that the solution is basic. The pH will be less than 7.
- Therefore, we can match this with option (t) "less than 7".

### Step 2: Analyze the second mixture (B)
**Mixture:** 0.1 M NaCl + 0.1 M NaNO₃

1. **Identify the components:**
- Both NaCl and NaNO₃ are neutral salts.

2. **Calculate pH:**
- Since both solutions are neutral, the resulting pH will be 7.
- Therefore, we can match this with option (r) "7".

### Step 3: Analyze the third mixture (C)
**Mixture:** 0.1 M NH₄Cl + 0.1 M NaOH

1. **Identify the components:**
- NH₄Cl is a salt of a weak base (NH₃) and a strong acid (HCl).
- NaOH is a strong base.

2. **Calculate pH:**
- The presence of NaOH will make the solution basic. The pH will be greater than 7.
- Therefore, we can match this with option (s) "greater than 7".

### Step 4: Analyze the fourth mixture (D)
**Mixture:** 0.5 M HCl + 0.1 M NH₄OH

1. **Identify the components:**
- HCl is a strong acid.
- NH₄OH (ammonium hydroxide) is a weak base.

2. **Calculate the effective concentration of H⁺ ions:**
- Normality of HCl = 0.5 N.
- Normality of NH₄OH = 0.1 N.
- Using the same formula:
\[ [H^+] = \frac{0.5V - 0.1V}{2V} = \frac{0.4V}{2V} = 0.2 \]

3. **Calculate pH:**
- pH = -log(0.2) ≈ 0.7.
- Therefore, we can match this with option (p) "0.7".

### Final Matching:
- A → t (less than 7)
- B → r (7)
- C → s (greater than 7)
- D → p (0.7)