Question

The crown ethers are heterocyclic polyethers, usually with at least four oxygen atoms.
The 12 - crown - 4 – ether contains __________ carbon atoms.
A. 12
B. 4
C. 8
D. 16

Answer 1

Before solving this question, we should know what polyethers are. The joining or polymerization of the number of monomers (simpler compounds) to form organic compounds are called Polyethers. They can be network-like or chain-like.

Complete step by step solution:
The cyclic chemical compounds have numerous ether groups. Cyclic oligomers of ethylene oxide, the repeating unit is ethyleneoxy are the most common Crown ethers. Tetramer (n=4 ), pentamer (n=5), and hexamer (n=6) are some important members of this series.
Crown ethers form complexes by binding with certain cations. The exterior of the ring is hydrophobic and the oxygen atoms situated at the interior of the ring are bonded with cation forms salts that are easily mixable in nonpolar solvents that are the reason it is used in phase transfer catalysis. The affinity of the crown ethers for cations affects the denticity of the polyether.

12 –crown– 4- ether structure
The molecular formula of this is ${{C}_{8}}{{H}_{16}}{{O}_{4}}$

Additional information: The macrocyclic polyethers contain hydrogen, oxygen, and carbon atoms. Every oxygen atom is constricted between two carbon atoms forming a conformation with the hole called as a crown. They have a strong capacity for strong solvency binding cations in their central chamber/cavity. The size of ring systems, alkyl side chains, and the functional groups decide the solvency capacity of the ion. The host is the Crown ether and the guest is Ionic species. Crown compounds lock the ionic species in the cavity. It is known as host-guest chemistry. Host-Guest Chemistry plays a vital role in various biological complex reactions, and helps in the development of pharmaceutical companies. It also helps in the catalysis and sensors. New designs of it open more fields of research.

So, Option (C) – 8 is correct.

Note: Crown ethers are used in the analytical chemical reagents. It helps in the acceleration of chemical reactions as it promotes the solubility of inorganic compounds in the organic solvents. It takes the inorganic catalysts to the organic phase. It is also used in drug delivery.