Organometallic Complexes Their Uses

Hint: Iron catalyst is used in Haber's process.
Explanation:

(1) The Haber process, also called the Haber–Bosch process, is the main industrial procedure for the production of ammonia. The catalyst used in the Haber’s process is iron (Fe), often promoted with small amounts of potassium oxide (K₂O), aluminum oxide (Al₂O₃), and sometimes calcium oxide (CaO) to enhance its efficiency and stability.

The iron catalyst provides a surface for nitrogen and hydrogen gases to react, lowering the activation energy and increasing the rate of ammonia formation without being consumed in the reaction.

(2) The Wacker oxidation involves the addition of water to the alkene, followed by oxidation to form an aldehyde or ketone. Palladium(II) chloride (PdCl₂) and copper(II) chloride (CuCl₂) are the primary catalysts, with copper acting as a co-catalyst or oxidant for palladium.

The reaction proceeds via a catalytic cycle where palladium(II) oxidizes the alkene, water is added to the resulting palladium complex, and the palladium is reoxidized by copper(II) and ultimately by oxygen.

(3) Wilkinson's catalyst is usually obtained by treating rhodium(III) chloride hydrate with an excess of triphenylphosphine in refluxing ethanol. Triphenylphosphine serves as both a ligand and a two-electron reducing agent that oxidizes itself from oxidation state (III) to (V). The chemical formula is .

It is highly effective in selectively adding hydrogen across the double bond of alkenes, leading to the formation of alkanes.

(4) The Ziegler-Natta catalyst typically consists of a transition metal compound (e.g., titanium tetrachloride) and an organoaluminum compound (e.g., triethylaluminum). These components work together to facilitate the insertion of alkene monomers into a growing polymer chain.

is known as Ziegler catalyst. Hence, option 1 is the correct answer.