Problem 13 - 43 Years JEE ADVANCED (1978-2020) + JEE MAIN Chapterwise & Topicwise Solved Papers Chemistry

Question

The compound which is not isomeric with diethyl ether is (a) \(n\)-propyl methyl ether (b) butan-1-ol (c) 2-methylpropan-2-ol (d) butanone

Step-by-Step Solution

Answer

Option (d) butanone is not isomeric with diethyl ether.

Step 1: Understanding Isomers

Isomers are compounds that have the same molecular formula but different structures and potentially different properties. To determine which compound is not isomeric with diethyl ether, we need to compare the molecular formula of diethyl ether to that of the given options.

Step 2: Determine Molecular Formula of Diethyl Ether

Diethyl ether is an ether with the formula \(C_4H_{10}O\). This means the molecular structure of diethyl ether is composed of 4 carbon atoms, 10 hydrogen atoms, and 1 oxygen atom.

Step 3: Evaluate Each Option

Compare the molecular formulas of the given compounds to \(C_4H_{10}O\):- **(a) \(n\)-propyl methyl ether**: \(C_4H_{10}O\)- **(b) butan-1-ol**: \(C_4H_{10}O\)- **(c) 2-methylpropan-2-ol**: \(C_4H_{10}O\)- **(d) butanone**: \(C_4H_8O\)

Step 4: Identify the Non-Isomer

Butanone, with the formula \(C_4H_8O\), does not match the molecular formula of diethyl ether \(C_4H_{10}O\). Therefore, butanone is not an isomer of diethyl ether.

Key Concepts

Molecular Formula

The molecular formula of a compound is essentially its chemical shorthand. It reveals the type and number of each atom present within the smallest unit of the compound. For instance, the molecular formula for diethyl ether is \(C_4H_{10}O\). This notation tells us that it consists of 4 carbon atoms, 10 hydrogen atoms, and one oxygen atom. This information is crucial to determine isomerism, as compounds with the same molecular formula can arrange their atoms differently to form isomers.When comparing compounds to see if they are isomers, the first step is to check if their molecular formulas match. If the formula differs, then the compounds cannot be isomers. Therefore, the concept of molecular formulas is foundational in chemistry to identify isomers and understand the distinct properties of compounds.

Diethyl Ether

Diethyl ether is a well-known organic compound with an ether group. The unique aspect of diethyl ether is its structural formula, which can exist in various arrangements due to the presence of the ether functional group. It primarily consists of two ethyl groups connected by an oxygen atom, represented as \(C_2H_5OC_2H_5\).

• Diethyl ether is often used as a solvent in laboratories due to its effectiveness in dissolving a wide range of chemical compounds.
• It is also recognized for being an early general anesthetic.

Understanding its molecular formula \(C_4H_{10}O\) and structure assists in recognizing its isomers. Despite having the same number of each type of atom, the arrangement of these atoms defines the properties and reactions of diethyl ether.

Functional Groups

Functional groups are specific groups of atoms within molecules that have characteristic properties and reactions. They serve as the foundation for organic chemistry reactions, determining the chemical behavior of the molecule. In diethyl ether, the functional group is the ether group, which is a carbon-oxygen-carbon linkage, denoted as \(\text{R-O-R'}\), where \(\text{R}\) and \(\text{R'}\) are alkyl groups.

• The ether group in diethyl ether is responsible for its relatively low polarity and reactivity.
• It impacts the molecule's boiling point and solubility characteristics, making it distinct from alcohols, which have a similar molecular formula but differ in functional groups.

By having an ether group, diethyl ether behaves differently in reactions than compounds with an alcohol or ketone group, despite sharing the same molecular formula. Functional groups therefore play a crucial role in the chemical reactions and physical properties of organic compounds.