Question

The homogeneous catalyst used in water-gas shift reaction is

• A. PdCl$_2$
• B. Cr$_2$O$_3$
• C. [RhCl(PPh$_3$)$_3$]
• D. [RuCl$_2$(bipyridyl)$_2$]

Hint:

Rhodium-phosphine complexes are classic homogeneous catalysts in CO–H$_2$O reactions.

Answer 1

The Correct Option is D

Step 1: Understanding water-gas shift reaction.
The reaction CO + H$_2$O → CO$_2$ + H$_2$ is used to produce hydrogen. When catalyzed homogeneously, the catalyst must dissolve in the reaction medium.
Step 2: Identify the homogeneous catalyst.
Rhodium-phosphine complexes such as [RhCl(PPh$_3$)$_3$] are well-known homogeneous catalysts for CO–H$_2$O transformations including the water-gas shift reaction.
Step 3: Elimination of other options.
Cr$_2$O$_3$ is heterogeneous.
PdCl$_2$ and Ru complexes do not function as standard homogeneous catalysts in this specific reaction.
Step 4: Conclusion.
Thus, the homogeneous catalyst is [RhCl(PPh$_3$)$_3$].