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

To identify Catalyst A and Catalyst B:

1. Catalyst A: In the conversion of ethylene and water to ethanol, a concentrated acid such as concentrated H+ is typically needed to drive the reaction efficiently. Therefore, Catalyst A is identified as concentrated H+.

2. Catalyst B: In the reverse reaction, where ethanol is converted back to ethylene, a dilute acid can be effective for dehygrogenation but often a concentrated acid is more commonly used. Given that both catalysts are derived from acidic solutions, Catalyst B can be assumed to be dilute H+.

Thus, the identities of the catalysts are: Catalyst A: conc H+ and Catalyst B: dilute H+.