What function does `HNO_(3)` serve in the reaction of benzene with `I_(2)` to produce iodobenzene ?

Options

A. The `HNO_(3)` convert the `I^(-)" to "I_(2)`
B. `HNO_(3)" serve as a catalyst"`
C. `HNO_(3)" convert " I_(2)" to HI"`
D. `HNO_(3)" conver " I_(2)" to "I^(+)`

Answer

To understand the function of `HNO3` in the reaction of benzene with `I2` to produce iodobenzene, we can break down the process step by step:

### Step 1: Understanding the Reaction
Benzene (C6H6) is an aromatic hydrocarbon that can undergo electrophilic substitution reactions. In this case, we want to substitute one of the hydrogen atoms on the benzene ring with an iodine atom to form iodobenzene (C6H5I).

### Step 2: Role of Iodine (I2)
Iodine (I2) itself is not a strong enough electrophile to react directly with benzene. For the reaction to proceed, we need to generate a more reactive species, which is the iodinium ion (I+).

### Step 3: Function of HNO3
This is where `HNO3` (nitric acid) comes into play. When `HNO3` is added to the reaction mixture containing `I2`, it facilitates the conversion of `I2` into the more reactive iodinium ion (I+). The reaction can be summarized as follows:

\[ I2 + HNO3 \rightarrow I^+ + HNO2 + H2O \]

In this reaction, `HNO3` acts as an oxidizing agent, helping to generate the electrophile (I+) necessary for the substitution reaction.

### Step 4: Electrophilic Attack
Once the iodinium ion (I+) is formed, it can now effectively attack the benzene ring. The electrophilic substitution occurs where the I+ ion replaces one of the hydrogen atoms on the benzene ring, resulting in the formation of iodobenzene:

\[ C6H6 + I^+ \rightarrow C6H5I + H^+ \]

### Step 5: Conclusion
In summary, the function of `HNO3` in the reaction of benzene with `I2` is to convert `I2` into the more reactive iodinium ion (I+), which can then successfully react with benzene to form iodobenzene.

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