Catalysts are required for the production of both ethanol from ethylene and ethylene from ethanol - HSC - SSCE Chemistry - Question 2 - 2006 - Paper 1

To determine the identities of Catalyst A and Catalyst B, we consider the processes of converting ethylene to ethanol and ethanol to ethylene.

1. Catalyst A is involved in the hydration of ethylene to form ethanol. The reaction typically requires a strong acid, often concentrated sulfuric acid or concentrated H⁺ ions that facilitate the breakage of the double bond in ethylene, allowing the addition of water. Thus, Catalyst A is likely to be conc H⁺.

2. Catalyst B is needed for the dehydration of ethanol back into ethylene. During this process, a weaker acid is often effective, which can be provided by dilute acids. Therefore, Catalyst B is associated with the conversion process where a more diluted acid is sufficient. Thus, Catalyst B is likely to be dilute H⁺.

Based on the table provided, the correct matching would be:

• Catalyst A (conc H⁺)
• Catalyst B (dilute H⁺)

Therefore, the identities of Catalyst A and Catalyst B are option (D): conc H⁺ for Catalyst A and dilute H⁺ for Catalyst B.