Cartain materials such as turpentine oil, unsaturated organic compound, phosophorus, metals such as `Zn`, and `Pb`, etc., can absorb `O_(2)` from air in the presence of `H_(2)O`, which is converted to absorb `O_(2)` from air in the presence of `H_(2)O`, which is converted to `H_(2)O_(2)`. This is called autoxidation. Intermolecular redox reactions are those in which one molecule is oxidised and the other is reduced. Intramolecular redox reactions are those in which oen atom of a molecule is oxidised and the other atom is reduced.
Which of the following reactions is`//`are intermolecular redox reaction `(s)`

Options

A. `5KI+KIO_(3)+6HClrarr3I_(2)+6KCl+3H_(2)O`
B. `Fe+N_(2)H_(4)rarrNH_(3)+Fe(OH)_(2)`
C. `NO_(3)^(ө)+H_(2)S+H_(2)O+H^(o+)rarrNH_(4)^(o+)+HSO_(4)^(ө)`
D. `CrO_(7)^(2-)+2overset(ө)OHrarr2CrO_(4)^(2-)+H_(2)O`s

Explanation

To determine which of the given reactions are intermolecular redox reactions, we need to analyze the oxidation states of the elements involved in each reaction. An intermolecular redox reaction occurs when one molecule is oxidized (loses electrons) and another molecule is reduced (gains electrons).

Let's break down the analysis step by step:

### Step 1: Analyze the Reactions
We will examine each reaction provided in the question to identify the changes in oxidation states.

#### Reaction A:
- **Reactants:** KI and KIO3
- **Oxidation States:**
- K in KI: -1
- I in KIO3: +5
- **Products:** I2
- **Oxidation States:**
- I in I2: 0
- **Change:**
- I changes from -1 (in KI) to 0 (in I2) - oxidation.
- I changes from +5 (in KIO3) to 0 (in I2) - reduction.

**Conclusion:** This is an intermolecular redox reaction.

#### Reaction B:
- **Reactants:** Fe and N2H4
- **Oxidation States:**
- Fe: 0
- N in N2H4: -2
- **Products:** NH3
- **Oxidation States:**
- N in NH3: -3
- Fe changes to +2.

**Change:**
- N changes from -2 (in N2H4) to -3 (in NH3) - reduction.
- Fe changes from 0 to +2 - oxidation.

**Conclusion:** This is also an intermolecular redox reaction.

#### Reaction C:
- **Reactants:** NO3^- and H2S
- **Oxidation States:**
- N in NO3^-: +5
- S in H2S: -2
- **Products:** NH4+ and HSO4^-
- **Oxidation States:**
- N in NH4+: -3
- S in HSO4^-: +6

**Change:**
- N changes from +5 (in NO3^-) to -3 (in NH4+) - reduction.
- S changes from -2 (in H2S) to +6 (in HSO4^-) - oxidation.

**Conclusion:** This is also an intermolecular redox reaction.

#### Reaction D:
- **Reactants:** Cr in two different states
- **Oxidation States:**
- Cr: +6 in both cases.

**Change:**
- There is no change in oxidation state for Cr.

**Conclusion:** This is not an intermolecular redox reaction.

### Step 2: Final Conclusion
The reactions that are intermolecular redox reactions are A, B, and C. The reaction D does not qualify as it does not involve any change in oxidation states.

### Summary of Answers:
- **Correct Options:** A, B, and C are intermolecular redox reactions.