**From CH3-CH2-CH2-OH or C6H5OH will not react with the mixture of NaBr and H2SO4 and why? Explain in detail.**

**Introduction:**
The reaction between CH3-CH2-CH2-OH (propanol) or C6H5OH (phenol) and the mixture of NaBr and H2SO4 does not occur because the conditions required for the reaction to take place are not met. The reaction in question is the formation of an alkyl bromide through an SN2 reaction. Let's discuss why these compounds do not react.

**Explanation:**

1. **SN2 Reaction:** The reaction between NaBr and H2SO4 is a classic example of the preparation of alkyl bromides through an SN2 (substitution nucleophilic bimolecular) reaction. In this reaction, the bromide ion (Br-) acts as the nucleophile and replaces the leaving group (OH-) in the alcohol molecule.

2. **Conditions for SN2 Reaction:** For the SN2 reaction to occur, certain conditions need to be met:

a. **Strong Nucleophile:** A strong nucleophile is required to attack the carbon atom of the alcohol molecule. In the case of NaBr, the bromide ion (Br-) is a relatively weak nucleophile.

b. **Polar Aprotic Solvent:** A polar aprotic solvent is preferred to dissolve both the nucleophile and the substrate. However, the mixture of NaBr and H2SO4 is not a suitable solvent for the reaction.

c. **Primary or Secondary Substrate:** The substrate alcohol should be primary or secondary in order for the SN2 reaction to occur efficiently. In the case of propanol (CH3-CH2-CH2-OH), it is a primary alcohol, and in the case of phenol (C6H5OH), it is an aromatic compound. Both of these substrates are not suitable for the SN2 reaction.

3. **Propanol (CH3-CH2-CH2-OH):**
- Propanol is a primary alcohol, which means that the carbon atom attached to the hydroxyl group is also bonded to two other hydrogen atoms.
- Primary alcohols are generally less reactive towards SN2 reactions compared to secondary or tertiary alcohols.
- The nucleophilic substitution reaction between propanol and NaBr/H2SO4 does not occur efficiently due to the primary nature of propanol and the weak nucleophilic character of the bromide ion.

4. **Phenol (C6H5OH):**
- Phenol is an aromatic compound, and aromatic compounds have unique reactivity compared to aliphatic compounds.
- Phenol does not undergo SN2 reactions due to the presence of the aromatic ring.
- The reaction between phenol and NaBr/H2SO4 does not occur because the phenol molecule does not have a suitable leaving group that can be replaced by the nucleophile.

In conclusion, both propanol and phenol do not react with the mixture of NaBr and H2SO4 because they do not fulfill the necessary conditions for an SN2 reaction to take place. The primary nature of propanol and the aromatic character of phenol make them unsuitable for this type of nucleophilic substitution reaction.