Which of the following reaction does not form an ether ?

Options

A. `C_6H_6OH+RBroverset("aq.NaOH)rarr`
B. `CH_3-underset(CH_3)underset(|)overset(CH_3)overset(|)C-CH=CH_2+ROH+Hg("OOCCF"_3)_2overset(NaBF_4)rarr`
C. `(CH_3)_3"CCl"+C_2H_5O^(-)Na^(+)rarr`
D. `CH_3CH_2OHunderset(413K)overset(H_2SO_4)rarr`

Answer

To determine which of the following reactions does not form an ether, we will analyze each reaction step by step.

### Step 1: Analyze the First Reaction
The first reaction involves phenol (C6H5OH) reacting with RBr in the presence of aqueous NaOH.

- **Mechanism**: The NaOH acts as a base and abstracts a proton (H+) from phenol, resulting in the formation of the phenoxide ion (C6H5O^-). This negatively charged oxygen can then act as a nucleophile and attack the alkyl halide (RBr).
- **Product**: The product formed is an ether (C6H5OR).

**Conclusion**: The first reaction forms an ether.

### Step 2: Analyze the Second Reaction
The second reaction involves a compound (CH3C(CH3)2) reacting with ROH in the presence of HGOOCCH3O2 and NaDF4.

- **Mechanism**: The alcohol (ROH) can react with the alkyl group in a nucleophilic substitution reaction, leading to ether formation.
- **Product**: The product formed is an ether.

**Conclusion**: The second reaction also forms an ether.

### Step 3: Analyze the Third Reaction
The third reaction involves CH3CCl3 reacting with C2H5O^-.

- **Mechanism**: Here, C2H5O^- is expected to act as a nucleophile. However, due to steric hindrance around the carbon atom (CCl3), the nucleophile cannot attack effectively. Instead, it acts as a base and abstracts a proton (H+) from the adjacent carbon.
- **Product**: The product formed is an alkene (CH3C(CH3)=CH2) instead of an ether.

**Conclusion**: The third reaction does not form an ether.

### Step 4: Analyze the Fourth Reaction
The fourth reaction involves ethanol (CH3CH2OH) reacting with itself in the presence of H2SO4 at 413 K.

- **Mechanism**: H2SO4 acts as a dehydrating agent, removing a water molecule and facilitating the formation of an ether.
- **Product**: The product formed is diethyl ether (C2H5OC2H5).

**Conclusion**: The fourth reaction forms an ether.

### Final Conclusion
After analyzing all four reactions, we find that:
- The first reaction forms an ether.
- The second reaction forms an ether.
- The third reaction does not form an ether (it forms an alkene).
- The fourth reaction forms an ether.

Thus, the reaction that does not form an ether is the **third reaction**.