Question

A compound of the formula \(\mathrm{C}_{4} \mathrm{H}_{10} \mathrm{O}\) reacts with sodium and undergoes oxidation to give a carbonyl compound which does not reduce Tollen's reagent, the original compound is (a) sec-butyl alcohol (b) \(n\)-butyl alcohol (c) isobutyl alcohol (d) diethyl ether

Short answer

The original compound is (a) sec-butyl alcohol.

Step-by-step solution

Analyze the Reaction with Sodium

Given that the compound reacts with sodium, it suggests the presence of an alcoholic functional group. Alcohols react with sodium to produce hydrogen gas. Ethers, on the other hand, do not react with sodium.

Consider the Resulting Compound after Oxidation

The compound is oxidized to form a carbonyl compound. This indicates that the original compound is likely an alcohol, as alcohols can be oxidized to ketones or aldehydes, which are carbonyl-containing compounds.

Examine the Tollen's Reagent Test

The product does not reduce Tollen's reagent, which implies the carbonyl compound is a ketone. Tollen's reagent is typically reduced by aldehydes but not by ketones.

Evaluate the Options

Based on the information: - sec-butyl alcohol can be oxidized to a ketone. - n-butyl alcohol and isobutyl alcohol can be oxidized to aldehydes. - diethyl ether does not react with sodium nor does it contain an oxidizable alcohol group. Therefore, sec-butyl alcohol (option a) will produce a non-reducing carbonyl compound, consistent with a ketone.

Key concepts

Oxidation of Alcohols

In organic chemistry, the oxidation of alcohols is an important reaction that leads to the formation of carbonyl compounds. This process involves the conversion of alcohols into aldehydes, ketones, or acids, depending on the type of alcohol. For primary alcohols, oxidation typically results in aldehydes, which can be further oxidized to carboxylic acids. Secondary alcohols, on the other hand, are oxidized to ketones, which cannot be further oxidized under mild conditions.

The oxidation reaction proceeds via the removal of hydrogen atoms from the alcohol molecule. A common reagent used for such oxidations is chromic acid, although many others exist, each with their preferred conditions and effects. This reaction is vital in synthetic organic chemistry, where controlling the oxidation state is crucial for the development of complex molecules. Understanding these pathways allows chemists to predict and manipulate chemical behaviors effectively.

Tollen's Reagent Test

Tollen's reagent is a classic chemical tool used to distinguish between aldehydes and ketones. It consists of a basic solution of silver nitrate dissolved in ammonia, which is capable of oxidizing aldehydes to carboxylate ions. During this reaction, the silver ion is reduced to metallic silver, which precipitates as a mirror-like deposit.

This test is particularly useful because ketones do not react with Tollen's reagent. Therefore, if a carbonyl compound does not reduce Tollen's reagent, it indicates that the compound is a ketone. This trait is instrumental in organic chemistry for identifying unknown compounds and determining the nature of functional groups within those compounds.

Functional Groups in Compounds

Functional groups are specific groups of atoms within molecules that have characteristic properties and reactivity. These groups determine how a molecule will react in a chemical reaction. Common functional groups in organic chemistry include alcohols, aldehydes, ketones, carboxylic acids, ethers, and many more.

Recognizing functional groups in compounds helps predict the types of reactions the substance can undergo. For instance, alcohols are characterized by the presence of an -OH group, which readily participates in oxidation reactions. Understanding these groups is crucial for anyone studying organic chemistry because they directly influence the chemical behavior and properties of organic molecules. This knowledge is fundamental in both experimental and theoretical aspects of chemistry.

Chemical Reactions Analysis

Analyzing chemical reactions involves looking at the reactants and products involved, as well as the conditions under which the reaction occurs. It’s essential to understand both the stoichiometry and the mechanism of reactions, which describe the proportions of reactants and products, and the step-by-step process of molecular transformations, respectively.

For instance, considering a reaction where an alcohol is oxidized to a ketone, it's important to know the specific reactants: the alcohol and the oxidizing agent. The products need to be identified correctly to ensure the reaction has proceeded as expected. The conditions, such as temperature and solvents, can significantly impact the reaction pathway and the yield. Chemical reaction analysis allows us to optimize these parameters for desired outcomes in synthesis and practical applications.