Question

Match List-I with List-II. 

List-I	Transition metal/compound
A	V₂O₅
B	Fe
C	PdCl₂
D	Ni complex

 

List-II	Catalytic role
I	Preparation of ammonia from N₂/H₂ mixture
II	Polymerisation of alkynes
III	Oxidation of SO₂ to SO₃
IV	Preparation of ethyne to ethene

• A. A-II, B-I, C-IV, D-III
• B. A-IV, B-III, C-II, D-I
• C. A-II, B-I, C-III, D-IV
• D. A-III, B-I, C-IV, D-II

Hint:

Remember important catalysts: \(V_2O_5\) for Contact process and Fe for Haber process.

Answer 1

The Correct Option is D

Step 1: Understanding the Topic:
The topic of this question is the industrial application of d-block elements and their compounds as catalysts. Transition metals are highly effective as catalysts due to their ability to adopt multiple oxidation states and their ability to form unstable complexes with reactant molecules. By providing a surface for reactants to adsorb or by forming intermediate species, they lower the activation energy of important industrial reactions. This makes the production of fundamental chemicals like ammonia and sulfuric acid economically viable.
Step 2: Key Formulas and Approach:
The approach involves identifying the specific catalyst used in well-known "named" industrial processes. We categorize each catalyst based on its physical form and the specific chemical reaction it facilitates:
Contact Process: Oxidation of $SO_2$ to $SO_3$.
Haber Process: Synthesis of $NH_3$ from $N_2$ and $H_2$.
Wacker Process: Oxidation of alkenes to aldehydes.
Polymerization: Joining of small molecules into long chains.

Step 3: Detailed Explanation:

A. V$_2$O$_5$ (Vanadium Pentoxide): This is the key catalyst in the Contact Process. In this process, sulfur dioxide is converted to sulfur trioxide, which is then used to make sulfuric acid. The oxide provides an oxygen-transfer mechanism through the switching of Vanadium's oxidation states. Thus, A matches with III.
B. Fe (Iron): Finely divided iron, along with promoters like $Al_2O_3$ and $K_2O$, is used in the Haber Process. This process is the foundation of the fertilizer industry as it converts atmospheric nitrogen into ammonia. Iron helps in weakening the extremely strong $N \equiv N$ triple bond. Thus, B matches with I.
C. PdCl$_2$ (Palladium Chloride): This metal salt is used in the Wacker Process. This industrial method allows for the direct oxidation of ethene to ethanal (acetaldehyde) in the presence of air and a $PdCl_2/CuCl_2$ catalytic system. Thus, C matches with IV.
D. Ni complex: Certain organometallic complexes of Nickel are used to catalyze the cyclic polymerization of alkynes. For example, they can facilitate the conversion of ethyne (acetylene) into benzene or other cyclic oligomers. Thus, D matches with II.
Step 4: Final Answer:
The correct matching sequence is A-III, B-I, C-IV, D-II, which corresponds to option (D).