Which of the following reactions do not involve oxidation reduction ?
I. `2Cs+2H_(2)Orarr2CsOH+H_(2)`
II. `2CuI_(2)rarr2CuI+I_(2)`
III. `NH_(4)Br+KOHrarrKBr+NH_(3)+H_(2)O`
IV. `4KCN+Fe(CN)_(2)rarrK_(4)[Fe(CN)_(6)]`

Options

A. `I,II`
B. `I,III`
C. `I,III,IV`
D. `III,IV`

Explanation

To determine which of the given reactions do not involve oxidation-reduction (redox) processes, we will analyze each reaction one by one.

### Step 1: Analyze Reaction I
**Reaction I:**
\[ 2Cs + 2H_2O \rightarrow 2CsOH + H_2 \]

- **Oxidation States:**
- Cesium (Cs) in reactants: 0 (elemental form)
- Cesium (Cs) in products: +1 (in CsOH)
- Hydrogen (H) in water: +1
- Hydrogen (H) in products (H2): 0

- **Change in Oxidation States:**
- Cs: 0 to +1 (oxidation)
- H: +1 to 0 (reduction)

Since there is both oxidation and reduction occurring, this is a redox reaction.

### Step 2: Analyze Reaction II
**Reaction II:**
\[ 2CuI_2 \rightarrow 2CuI + I_2 \]

- **Oxidation States:**
- Copper (Cu) in CuI2: +1
- Copper (Cu) in CuI: +1
- Iodine (I) in CuI2: -1
- Iodine (I) in I2: 0

- **Change in Oxidation States:**
- Cu: +1 to +1 (no change)
- I: -1 to 0 (oxidation)

Here, iodine is oxidized, but copper does not change its oxidation state. This reaction does involve oxidation but does not involve reduction. Therefore, this reaction is not a complete redox reaction.

### Step 3: Analyze Reaction III
**Reaction III:**
\[ NH_4Br + KOH \rightarrow KBr + NH_3 + H_2O \]

- **Oxidation States:**
- Nitrogen (N) in NH4Br: -3
- Nitrogen (N) in NH3: -3
- Bromine (Br) in NH4Br: -1
- Bromine (Br) in KBr: -1
- Oxygen (O) in H2O: -2
- Hydrogen (H) in H2O: +1

- **Change in Oxidation States:**
- N: -3 to -3 (no change)
- Br: -1 to -1 (no change)
- O and H do not change their oxidation states in a way that involves redox.

Since there are no changes in oxidation states, this is not a redox reaction.

### Step 4: Analyze Reaction IV
**Reaction IV:**
\[ 4KCN + Fe(CN)_2 \rightarrow K_4[Fe(CN)_6] \]

- **Oxidation States:**
- K: +1 (remains +1)
- C in CN: -1 (remains -1)
- Fe in Fe(CN)2: +2 (remains +2)
- C in K4[Fe(CN)6]: -1 (remains -1)

- **Change in Oxidation States:**
- K: +1 to +1 (no change)
- C: -1 to -1 (no change)
- Fe: +2 to +2 (no change)

Since there are no changes in oxidation states, this is also not a redox reaction.

### Conclusion
The reactions that do not involve oxidation-reduction are:
- **Reaction II:** \( 2CuI_2 \rightarrow 2CuI + I_2 \)
- **Reaction III:** \( NH_4Br + KOH \rightarrow KBr + NH_3 + H_2O \)
- **Reaction IV:** \( 4KCN + Fe(CN)_2 \rightarrow K_4[Fe(CN)_6] \)

Thus, the answer is that reactions II, III, and IV do not involve oxidation-reduction.