Fill in the blanks by choosing the appropriate word/words from those given in the brackets.
(Monohydric, dihydric, trihydric, nitration, sulfonation, resonance stabilizaton, acidic, basic, `FeCl_(3)ZnCl_(2)`, more, less, aldehydes, ketones, Tollens' reagent, Luca's reagent, o-nitrophenol, p-nitrophenol, ethene, diethyl ether, fit, unfit, be, not be, `O_(2),Cl_(2)`, alkyl halides, oxonium, hydronium, alkyl, lone pairs of electrons, ethyl iodide, ethyl hydrogen sulfate, perchlorodiethyl ether, methyl iodide, ethyl hydrogensulfate, perchlorodiethyl ether, methyl iodide, dialkyl, hydrogen bonding, violet, green)
Ethers act as Lewis base due to the presence of.......on oxygen.

Explanation

**Step-by-Step Solution:**

1. **Understanding Ethers**: Ethers are organic compounds that contain an oxygen atom connected to two alkyl or aryl groups. The general structure of an ether can be represented as R-O-R', where R and R' are hydrocarbon chains.

2. **Defining Lewis Bases**: According to the Lewis concept, a Lewis base is defined as a substance that can donate an electron pair to an electron-deficient species (Lewis acid).

3. **Identifying the Key Feature**: The key feature that allows ethers to act as Lewis bases is the presence of lone pairs of electrons on the oxygen atom.

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