International General Certificate of Secondary Education (IGCSE) Chemistry Practice Exam

What conditions are necessary for manufacturing ethanol using ethene and steam?

1. 50°C, 40 atm, Phosphoric acid

2. 300°C, 60 atm, Phosphoric acid

3. 200°C, 70 atm, Sulfuric acid

4. 100°C, 10 atm, Sodium hydroxide

The correct answer is: 300°C, 60 atm, Phosphoric acid

The production of ethanol from ethene and steam occurs through a hydration reaction. The process requires specific conditions that favor the formation of ethanol while ensuring a reasonable rate of reaction. The correct answer includes a temperature of 300°C and a pressure of 60 atm, which create an environment conducive to the reaction. At higher temperatures, the reaction between ethene and steam proceeds faster, allowing for a more efficient process. Additionally, increasing the pressure increases the concentration of the reactants, thus promoting the conversion of ethene into ethanol. Phosphoric acid is used as a catalyst in this reaction, which enhances the reaction rate without being consumed in the process. This allows for more effective conversion of ethene to ethanol under the specified conditions. In contrast, other answers either propose conditions that are not suitable for the reaction, such as temperatures that are too low or pressures that may not sufficiently drive the reaction forward. Additionally, some options list the use of incorrect catalysts or unsuitable chemical agents for this hydration process. This highlights the importance of combining appropriate temperature, pressure, and a suitable catalyst to optimize the production of ethanol from ethene and steam.