UPSC CSE Prelims 1998
Consider the following statements about acetylene:
- It is used in welding industry.
- It is a raw material for preparing plastics.
- It is easily obtained by mixing silicon carbide and water of these statements.
EXPLANATION
Correct Option
Statement 1: Acetylene (C₂H₂) is extensively utilized in the welding industry, particularly in oxy-acetylene welding. The combustion of acetylene with oxygen produces a flame with a temperature exceeding 3300°C, making it highly effective for cutting and joining various metals.
Statement 2: Acetylene serves as a crucial raw material in the synthesis of plastics and synthetic rubber. Through polymerization, it can form polyacetylene, which was one of the earliest organic semiconductors and contributed to the development of conductive polymers.
Incorrect Options
Statement 3: The assertion that acetylene is obtained by mixing silicon carbide and water is incorrect. The reaction between silicon carbide (SiC) and water typically yields methane (CH₄) or other related hydrocarbons, not acetylene. Acetylene is commonly produced by the hydrolysis of calcium carbide (CaC₂) with water, as shown by the following reaction:
CaC₂ + 2H₂O → C₂H₂ + Ca(OH)₂
Since statement 3 is factually incorrect, options (b), (c), and (d), which include statement 3, are therefore incorrect.
