UPSC Prelims PYQ 1998: Statements about acetylene — uses and production

Consider the following statements about acetylene:

1. It is used in welding industry.
2. It is raw material for preparing plastics.
3. It is easily obtained by mixing silicon carbide and water.

Of these statements:

1. I and II are correct
2. I and III are correct
3. II and III are correct
4. I, II and III are correct

Explanation

Option (a) is correct

• Acetylene is widely used in oxy-acetylene welding and cutting because it produces a very high-temperature flame capable of melting metals. It also serves as an important chemical feedstock for manufacturing organic intermediates such as vinyl chloride, which is used to produce PVC and other plastics. Industrially, acetylene is obtained by the hydrolysis of calcium carbide (CaC₂ + 2H₂O → C₂H₂ + Ca(OH)₂), not from silicon carbide; therefore, statement III is incorrect, and only statements I and II are correct.

Answer: (a) I and II are correct