The repeating units of PTFE are: (a) \(\mathrm{F}_{2} \mathrm{C}=\mathrm{CF}_{2}\) (b) \(\mathrm{FCl} \mathrm{C}=\mathrm{CF}_{2}\) (c) \(\mathrm{F}_{3} \mathrm{C}-\mathrm{CF}_{3}\) (d) \(\mathrm{Cl}_{2} \mathrm{CH}-\mathrm{CH}_{3}\)

Polytetrafluoroethylene (PTFE), commonly known by the brand name Teflon, is a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. The primary feature of PTFE is its remarkable chemical resistance and ability to withstand high temperatures.
It's composed of carbon and fluorine atoms, where each carbon atom is bonded to two fluorine atoms in a polymer chain. This gives PTFE its non-stick properties and chemical inertness. Due to its high melting point (around 327°C or 620.6°F), it's also used in high-temperature environments.
In the given exercise, the solution correctly focuses on identifying the PTFE repeating unit by eliminating structures with atoms other than carbon and fluorine. This approach simplifies the process of distinguishing the correct chemical structure amidst multiple options.

In polymer science, the term 'polymer repeating unit' refers to the simplest repeatable section of a polymer chain that represents the entire polymer's structure. When polymers are formed through polymerization, these repeating units, also known as monomers, bind together to form long chains.
Understanding the polymer repeating unit is crucial because it defines the polymer's properties. For instance, in PTFE, the repeating unit is \( -CF_2-CF_2- \) which is entirely composed of carbon and fluorine atoms. The strength of the carbon-fluorine bond gives PTFE its thermal stability and resistance to solvents. When identifying a polymer repeating unit, as in the exercise, it's important to recognize the correct monomer and how it repeats to form the polymer chain.

Organic chemistry is a significant subject within the National Eligibility and Entrance Test (NEET), which is a qualifying examination for students who wish to study undergraduate medical courses in India. It encompasses the study of the structure, properties, composition, reactions, and preparation of carbon-containing compounds, which include not only hydrocarbons but also compounds with a multitude of other elements, including hydrogen, oxygen, nitrogen, halogens, phosphorus, silicon, and sulfur.
For NEET aspirants, understanding the structure and properties of chemicals like PTFE is crucial. It requires a strong grasp of molecular structures, bonding, and chemical reactions. The approach taken in the exercise - analyzing the chemical structure of PTFE and determining its repeating units - is a typical example of the kind of problem-solving skills that NEET Organic Chemistry questions aim to test. This integrative approach not only tests student's memory but also their ability to apply concepts in novel scenarios.