Question

What is pyrolysis? Name the products obtained by the pyrolysis of methane. State one use of each product.

Answer 1

Pyrolysis means cracking of heavier hydrocarbons to lower hydrocarbons. Its also defined as thermochemical decomposition of hydrocarbons at elevated temperature in the absence of oxygen.

Higher hydrocarbon $\stackrel{200-300{}^{0}C}{\to }$ Lower hydrocarbon

In the case of Methane,

CH_4(g) $\stackrel{200{}^{0}C}{\to }$ C_(s) + 2H₂ $∆$H = 74.9 kJ/mole

• The carbon black is used as a model compound for diesel soot for diesel oxidation experiments.
• It is mainly used as a reinforcing filler in tyres and other rubber products.
• In plastics, paints, and inks it is used as a colour pigment.