Which of the following is a correct statement?

FeO is non stoichiometric.

The correct answer is option 1. FeO is non stoichiometric.

Let us delve into each statement:

1. FeO is non stoichiometric:

Iron(II) oxide, commonly known as FeO, is often considered non-stoichiometric. Stoichiometry refers to the numerical relationship of elements in a compound, typically expressed by a chemical formula. In the case of FeO, it can deviate from strict stoichiometry due to the presence of iron vacancies or excess iron atoms. FeO can be represented by the formula Fe\(_{1-x}\)O, where \(x\) represents the fraction of iron vacancies. This non-stoichiometry is commonly observed in many metal oxides and is a result of defects in the crystal structure.

2. Reduction using Lindlar's catalyst converts 2-butyne into trans-2-butene:

Lindlar's catalyst is a palladium catalyst that is poisoned with lead or quinoline to reduce its reactivity. It is used for the selective hydrogenation of alkynes to alkenes. However, Lindlar's catalyst typically produces cis-alkenes rather than trans-alkenes. Therefore, 2-butyne would be expected to yield cis-2-butene rather than trans-2-butene upon reduction using Lindlar's catalyst

3. \(TiCl_4\) is used as Lindlar's catalyst in polymerization of ethyne:

This statement is incorrect. Lindlar's catalyst involves palladium, not titanium tetrachloride \((TiCl_4)\). Lindlar's catalyst consists of palladium deposited on a calcium carbonate or barium sulfate support and then poisoned with lead or quinoline. It is specifically used for the partial hydrogenation of alkynes, not for the polymerization of ethyne (also known as acetylene).

4. Acidic potassium permanganate is used in organic chemistry under the name of Baeyer's reagent:

Baeyer's reagent typically refers to an alkaline solution of potassium permanganate \((KMnO_4)\), not an acidic one. It is used to oxidize alkenes and alkynes to form diols or diketones, respectively. The alkaline nature of the solution helps to prevent over-oxidation of the organic substrate.

In summary:

The statement about FeO being non-stoichiometric is correct due to the presence of iron vacancies or excess iron atoms. The statement about the reduction using Lindlar's catalyst producing trans-2-butene is incorrect; it typically produces cis-2-butene. The statement about \(TiCl_4\) being used as Lindlar's catalyst in the polymerization of ethyne is incorrect; Lindlar's catalyst involves palladium, not titanium tetrachloride. The statement about acidic potassium permanganate being used in organic chemistry under the name of Baeyer's reagent is incorrect; Baeyer's reagent typically refers to an alkaline solution of potassium permanganate.