Explain the following with an example:
i. Kolbe's reaction
ii. Reimer-Tiemann reaction
iii. Williamon's ether synthesis
iv. Usymmetrical ether

Explanation

### Step-by-Step Solution:

#### i. Kolbe's Reaction
Kolbe's reaction is an electrochemical reaction that involves the decarboxylation of sodium salts of carboxylic acids. The reaction is commonly used to prepare salicylic acid from phenol.

1. **Starting Material**: Phenol (C6H5OH).
2. **Reaction with Sodium Hydroxide**: Phenol reacts with sodium hydroxide (NaOH) to form sodium phenoxide (C6H5O^-Na^+).
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