Crude oil is fractionally distilled to produce fractions - Edexcel - GCSE Chemistry - Question 5 - 2017 - Paper 1

Cracking is a process used in the oil industry to break down larger and heavier hydrocarbon molecules into smaller, more useful ones. This is typically achieved by heating these hydrocarbons and using catalysts.

One example of a hydrocarbon formed during the cracking of butane is ethylene (C₂H₄). The structural formula is:

      H   H
       \ /   
        C=C
       / \  
      H   H

This represents the double bond between two carbon atoms, along with single bonds to the hydrogen atoms.

Advantages of using hydrogen include:

1. Environmental Benefits: Hydrogen as a fuel produces only water vapor when combusted, which reduces greenhouse gas emissions.
2. Abundant Resource: Hydrogen can be produced from various sources, including water and organic materials.
3. Higher Efficiency: Hydrogen fuel cells are generally more efficient than internal combustion engines.

Disadvantages include:

1. Infrastructure Challenges: Limited availability of hydrogen filling stations can hinder adoption.
2. Production Concerns: The process of producing hydrogen can require fossil fuels, which may negate some environmental benefits.
3. Storage Issues: Hydrogen requires high-pressure storage or cryogenic temperatures, which can pose engineering challenges and safety concerns.