Define organic chemistry, aliphatic compounds, functional group, molecular formula, and allotropy. Explain why CO2 is inorganic and why carbon is unique.

• i) Organic chemistry: The branch of chemistry that studies the structure, properties, composition, reactions, and preparation of carbon-containing compounds, primarily those with carbon-hydrogen bonds.
• ii) Aliphatic compounds: Organic compounds that consist of carbon and hydrogen joined together in straight chains, branched chains, or non-aromatic rings. They do not contain benzene rings.
• iii) Functional group: A specific group of atoms within a molecule that is responsible for the characteristic chemical reactions of that molecule.
• iv) Molecular formula: A chemical formula that shows the total number of atoms of each element in a molecule, without indicating their arrangement.
• v) Allotropy: The property of some chemical elements to exist in two or more different forms (allotropes) in the same physical state, differing in atomic arrangement and properties.

Carbon dioxide is generally considered an inorganic compound because it lacks carbon-hydrogen (C-H) bonds, which are characteristic of most organic compounds.

Carbon is unique due to its ability to form four strong covalent bonds (tetravalency) and its exceptional capacity for catenation, forming long chains, branched chains, and rings with other carbon atoms. This allows for the formation of an immense variety of stable compounds.

• i) 2,2,3,3-Tetramethylbutane

  $$\begin{array}{c} \mathrm{CH_3} \\ | \\ \mathrm{CH_3}-\mathrm{C}-\mathrm{C}-\mathrm{CH_3} \\ | \quad | \\ \mathrm{CH_3} \quad \mathrm{CH_3} \end{array}$$

  or $(CH_3)_3C-C(CH_3)_3$

• ii) Acetylene

  $$\mathrm{H}-\mathrm{C} \equiv \mathrm{C}-\mathrm{H}$$

• iii) (E)-1-Bromo-2-chloro-1-fluoro-2-iodoethene

The compounds to be named are not provided in the question. Please provide the structures for part (e).