Petroleum refining involves: MCQ with Answer and Explanation

Explanation:
Each carbon in diamond is sp³ hybridized and covalently bonded to four others in a tetrahedral geometry, forming a rigid 3D network. Graphite has a layered structure.

Explanation:
Smelting is a reduction process, not concentration. Concentration (beneficiation) methods include gravity separation, magnetic separation, froth flotation, and leaching (chemical). Smelting involves heating concentrated ore with a reducing agent to extract metal. For example, hematite concentrated by washing, then smelted in blast furnace.

Explanation:
Ethylene (C₂H₄) is systematically named ethene. The -ene suffix indicates a double bond. Ethane is C₂H₆, ethyne (acetylene) is C₂H₂, methane is CH₄. Ethene is an important petrochemical used to make polythene.