Problem 21 - 43 Years JEE ADVANCED (1978-2020) + JEE MAIN Chapterwise & Topicwise Solved Papers Chemistry

Question

Wilkinson catalyst is: (a) \(\left[\left(\mathrm{Ph}_{3} \mathrm{P}\right)_{3} \mathrm{IrCl}\right]\) (b) \(\left[\left(\mathrm{Et}_{3} \mathrm{P}\right)_{3} \mathrm{RhCl}\right]\) (c) \(\left[\left(\mathrm{Ph}_{3} \mathrm{P}\right)_{3} \mathrm{RhCl}\right]\) (d) \(\left[\left(\mathrm{Et}_{3} \mathrm{P}\right)_{3} \mathrm{IrCl}\right]\)

Step-by-Step Solution

Answer

Option (c): \([\text{RhCl}(\text{PPh}_3)_3]\) is the Wilkinson catalyst.

Step 1: Understand Wilkinson Catalyst

Wilkinson catalyst is a chemical compound known for its use in hydrogenation reactions. It is a homogeneous catalyst with the formula \([\text{RhCl}(\text{PPh}_3)_3]\), where Rh stands for rhodium, Cl for chloride, and PPh represents triphenylphosphine.

Step 2: Analyze the Options

Examine the chemical formulas of the options provided: - (a) \([\text{IrCl}(\text{PPh}_3)_3]\)- (b) \([\text{RhCl}(\text{PEt}_3)_3]\)- (c) \([\text{RhCl}(\text{PPh}_3)_3]\)- (d) \([\text{IrCl}(\text{PEt}_3)_3]\)We need to find the one that matches the Wilkinson catalyst formula.

Step 3: Match the Formula

The formula for Wilkinson catalyst is \([\text{RhCl}(\text{PPh}_3)_3]\). Compare this with the given options. Option (c) \([\text{RhCl}(\text{PPh}_3)_3]\) exactly matches the structure of Wilkinson catalyst.

Step 4: Select the Correct Answer

Since option (c) matches the formula for the Wilkinson catalyst, select option (c) as the correct answer.

Key Concepts

Understanding Homogeneous Catalysts

Homogeneous catalysts are fascinating components in chemistry, especially in industrial processes. They are called 'homogeneous' because they exist in the same phase as the reactants, typically in a dissolved state within a solution. This characteristic allows the catalyst to interact more thoroughly with the reactants, leading to higher reaction rates.

• Just like a soup mix dissolving in water, a homogeneous catalyst blends seamlessly within the reactants.
• This uniform mixing results in even distribution, ensuring each molecule of reactant encounters the catalyst.

The Wilkinson catalyst is a prime example of a homogeneous catalyst. Made up of rhodium, it is used widely because of its ability to evenly catalyze hydrogenation reactions.

Exploring Hydrogenation Reactions

Hydrogenation reactions are processes where hydrogen is added to other compounds, usually in the presence of a catalyst. This addition of hydrogen can convert unsaturated compounds like alkenes and alkynes into saturated compounds such as alkanes.

• Think of it as the process of "saturating" a molecule by adding the simplest element, hydrogen.
• The key purpose is often to solidify or stabilize a compound.

Catalysts such as the Wilkinson catalyst play a vital role here. By breaking the H-H bond in molecular hydrogen, they enable the hydrogen atoms to bind to other organic molecules. In an industrial setting, this is crucial for producing margarine from vegetable oils, among other products.

Delving into Complex Compounds

Complex compounds, like the Wilkinson catalyst, are vital players in many chemical reactions. These compounds are characterized by their intricate structures consisting of a central metal atom bonded to one or more ligands.

• The central metal atom, rhodium in the case of Wilkinson catalyst, coordinates to the surrounding ligands, creating a stable and effective catalytic entity.
• Triphenylphosphine ligands around rhodium are responsible for the catalytic prowess of the Wilkinson catalyst.

This structure allows complex compounds to function effectively in reactions by providing a controlled environment for the catalyzed process. They bind to reactants in specific orientations, facilitating reactions with precision and efficiency.