What are ethers? How are they classified?

Explanation

### Step-by-Step Solution:

1. **Definition of Ethers**:
Ethers are organic compounds that consist of an oxygen atom connected to two alkyl or aryl groups. They can be represented by the general formula R-O-R', where R and R' can be the same or different hydrocarbon chains.

2. **Structure of Ethers**:
In ethers, one hydrogen atom from a hydrocarbon (like methane, CH4) is replaced by an alkoxy group (R-O). For example, if we take methane (CH4) and replace one hydrogen with an -O-R group, we can form an ether like methyl ether (CH3-O-CH3).

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