Conc. `HNO_3` reacts with `I_2` to form:

Options

A. `HI`
B. `HOI`
C. `HIO_(2)`
D. `HIO_3`

Explanation

To solve the question regarding the reaction of concentrated HNO3 with I2, we can follow these steps:

### Step-by-Step Solution:

1. **Identify Reactants**: The reactants in this reaction are concentrated nitric acid (HNO3) and iodine (I2).

2. **Write the Reaction**: When I2 reacts with concentrated HNO3, the primary product formed is periodic acid (HIO3) along with nitrogen dioxide (NO2) as a byproduct. The reaction can be represented as:
\[ I_2 + HNO_3 \rightarrow HIO_3 + NO_2 \]

3. **Balance the Reaction**:
- Start by balancing the iodine atoms. Since there are 2 iodine atoms in I2, we need 2 HIO3:
\[ I_2 + HNO_3 \rightarrow 2 HIO_3 + NO_2 \]
- Now, balance the hydrogen atoms. Each HIO3 has one hydrogen, so we need 2 HNO3 to provide 2 hydrogen atoms:
\[ I_2 + 4 HNO_3 \rightarrow 2 HIO_3 + 4 NO_2 + 2 H_2O \]
- Finally, check the balance of nitrogen and oxygen atoms to ensure the equation is balanced.

4. **Final Balanced Equation**:
After balancing, the final equation can be simplified to:
\[ I_2 + 10 HNO_3 \rightarrow 6 HIO_3 + 4 NO_2 + 2 H_2O \]

5. **Identify the Product**: The main product of the reaction is periodic acid (HIO3).

6. **Choose the Correct Option**: From the options provided (HI, HOI, HIO2, HIO3), the correct answer is HIO3.

### Final Answer:
The reaction of concentrated HNO3 with I2 forms periodic acid (HIO3).