In the following reaction sequence :
`R-OH overset(P+I_(2))rarr R-I overset(AgNO_(2))rarr RNO_(2) overset(HNO_(2))rarr ` no reaction.
The alcohol is a :

Options

A. primary alcohol
B. secondary alcohol
C. tertiary alcohol
D. phenol

Explanation

To determine which alcohol corresponds to the reaction sequence provided, we will analyze each step of the reaction and identify the type of alcohol involved.

### Step-by-Step Solution:

1. **Identify the Reaction Sequence**:
The given reaction sequence is:
\[ R-OH \overset{P + I_2}{\rightarrow} R-I \overset{AgNO_2}{\rightarrow} RNO_2 \overset{HNO_2}{\rightarrow} \text{no reaction} \]
This sequence is indicative of the Victor-Mayer test, which is used to differentiate between primary, secondary, and tertiary alcohols.

2. **Understanding the Victor-Mayer Test**:
- In the first step, the alcohol (R-OH) reacts with phosphorus and iodine to form an alkyl iodide (R-I).
- In the second step, the alkyl iodide reacts with silver nitrate (AgNO2) to form a nitro compound (RNO2).
- The final step involves treating the nitro compound with nitrous acid (HNO2), which typically leads to the formation of a diazonium salt or a stable compound.

3. **Analyzing the Types of Alcohol**:
- **Primary Alcohol (1°)**:
- Reacts in all steps and produces a colored product upon treatment with sodium hydroxide after the final step.
- **Secondary Alcohol (2°)**:
- Reacts similarly but produces a different color upon treatment with sodium hydroxide.
- **Tertiary Alcohol (3°)**:
- Does not react in the first step because it lacks an alpha hydrogen, thus no reaction occurs, leading to no further product formation.

4. **Conclusion**:
- Since the final product shows "no reaction," we can conclude that the alcohol must be a tertiary alcohol (3°) because it does not undergo the initial reaction with phosphorus and iodine due to the absence of alpha hydrogen.

### Final Answer:
The alcohol is a **tertiary alcohol**.