Answer the question on the basis of passage given below:

Strong oxidizing agents, oxidize toluene and its derivatives to benzoic acid. However, it is possible to stop the oxidation at the aldehyde stage with suitable reagents that convert methyl group to an intermediate that is difficult to oxidize further.

Reagents which do not have any action on ketone are:

A. Schiff's reagent

B. \(KMnO_4\)

C. Tollen's reagent

D. Fehlings solution

E. \(LiAlH_4\)

Choose the correct answer from the options given below:

A, C and D only

The correct answer is option 1. A, C and D only.

Let us delve into the detailed explanation of how each reagent interacts with ketones:

A. Schiff's Reagent:

Schiff's reagent is a solution of fuchsine dye that has been decolorized by sulfur dioxide. It reacts with aldehydes to form a colored compound, indicating the presence of the aldehyde group. The aldehyde group reacts with Schiff’s reagent, restoring the color of the dye. Ketones do not typically react with Schiff's reagent because they lack the reactive hydrogen atom directly bonded to the carbonyl group, which is necessary for this reaction. Schiff's reagent is specific for aldehydes and does not show a reaction with ketones.

B. Potassium Permanganate (\(KMnO_4\)):

\(KMnO_4\) is a strong oxidizing agent. It oxidizes aldehydes to carboxylic acids. Potassium permanganate can also oxidize certain ketones under vigorous conditions, particularly if the ketones have alpha-hydrogens (as in the case of certain cyclic ketones). However, in general, ketones are less reactive compared to aldehydes and are not as readily oxidized by \(KMnO_4\) under mild conditions. While \(KMnO_4\) can react with ketones, it is not as reactive with them as it is with aldehydes, and typically it requires harsher conditions to do so.

C. Tollen's Reagent:

Tollen's reagent consists of a solution of silver nitrate (\(AgNO_3\)) in ammonia. Tollen's reagent is used to test for aldehydes. It reacts with aldehydes to form a silver mirror on the walls of the test tube, due to the reduction of silver ions (\(Ag^+\)) to metallic silver. They are oxidized to carboxylate anions, and \(Ag^+\) is reduced to metallic silver. Tollen's reagent does not react with ketones because ketones do not readily undergo oxidation by this reagent. Tollen's reagent is specific for aldehydes and does not react with ketones.

D. Fehling's Solution:

Fehling's solution is a mixture of two solutions: Fehling's A (copper(II) sulfate) and Fehling's B (alkaline tartrate solution). Fehling's solution is used to detect aldehydes. The copper(II) ions are reduced to copper(I) oxide, which forms a red precipitate. They are oxidized to carboxylate ions, and copper(II) ions are reduced to form the red copper(I) oxide precipitate. Ketones do not react with Fehling's solution because they are not easily oxidized by this reagent. Fehling's solution is specific for aldehydes and does not react with ketones.

E. Lithium Aluminium Hydride (\(LiAlH_4\)):

\(LiAlH_4\) is a powerful reducing agent. It reduces carbonyl compounds, including ketones and aldehydes, to alcohols. \(LiAlH_4\) reduces ketones to secondary alcohols by donating hydride ions (\(H^-\)). It reduces aldehydes to primary alcohols. \(LiAlH_4\) reacts with ketones to reduce them to secondary alcohols.

Summary:

Schiff's reagent (A) does not react with ketones.

Tollen's reagent (C) does not react with ketones.

Fehling's solution (D) does not react with ketones.

Potassium permanganate (B) can react with ketones under vigorous conditions.

Lithium aluminium hydride (E) reacts with ketones to reduce them to alcohols.

Thus, the correct answer is: Option 1: A, C, and D only.