Write the equation for the reduction of propene to propane using a transition metal catalyst. Group of answer choices A. CH2CHCH3 + H2 + Pt —> CH3CH2CH3 + Pt B. CH2CHCH3 + Pt —> CH3CH2CH3 + Pt C. CH2CHCH3 + H2 + Pt —> CH3CH2CH3 D. CH2CHCH3 + H2 + Pt —> CH3CHCH3 + Pt E. CH2CHCH3 + H2 → CH3CH2CH3
The Correct Answer and Explanation is:
The correct equation for the reduction of propene (C3H6) to propane (C3H8) using a transition metal catalyst is:
C. CH2CHCH3 + H2 + Pt —> CH3CH2CH3
Explanation:
In this reaction, propene (C3H6) is a alkene containing a carbon-carbon double bond (C=C). The reaction involves hydrogenation, where hydrogen gas (H2) is added across the double bond to convert the alkene into an alkane. This is a common reaction in organic chemistry, typically facilitated by a transition metal catalyst, like platinum (Pt), which helps to speed up the reaction without being consumed in the process.
Here’s a step-by-step breakdown of the process:
- Hydrogenation of Propene:
The double bond in propene reacts with hydrogen (H2), breaking the bond and allowing each carbon atom in the double bond to bond with one hydrogen atom. This results in the formation of propane (C3H8), a saturated alkane. - Role of the Platinum Catalyst:
Platinum (Pt) serves as a heterogeneous catalyst. It provides a surface for the reaction to occur, allowing the hydrogen molecules to dissociate and interact with the propene more easily. Platinum does not change during the reaction; it just facilitates the hydrogen atoms’ interaction with the propene molecule, enabling the addition of hydrogen across the double bond. - Reaction Conditions:
The hydrogenation typically requires mild heat and pressure, depending on the conditions, but the platinum catalyst is essential for making the reaction occur at a reasonable rate.
Why other answers are incorrect:
- A. Incorrect, because it shows platinum (Pt) being consumed, which is not the case in a catalytic reaction.
- B. Incorrect, because it doesn’t show the hydrogen (H2) that is necessary for the hydrogenation.
- D. Incorrect, because this would not be a hydrogenation reaction — the structure suggests it’s adding hydrogen across the double bond incorrectly.
- E. Incorrect, the reaction should be catalytic and require platinum (Pt), and the equation is missing the catalyst.
Thus, the correct answer is C, where propene is reduced to propane using hydrogen and a platinum catalyst.
