Question

Match the compounds/ions in Column I with their properties/reactions in Column II. Indicate your answer by darkening the appropriate bubbles of the \(4 \times 4\) matrix given in the ORS. Column I Column II (A) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CHO}\) (p) gives precipitate with 2 ,4-dinitrophenylhydrazine (B) \(\mathrm{CH}_{3} \mathrm{C} \equiv \mathrm{CH}\) (q) gives precipitate with \(\mathrm{AgNO}_{3}\) (C) CN ^ (r) is a nucleophile (D) \(\mathrm{I}^{-}\) (s) is involved in cyanohydrin formation

Short answer

(A) corresponds to (p), (B) corresponds to (q), (C) corresponds to (s), and (D) corresponds to (r).

Step-by-step solution

Identify Reactivity of Each Compound/Ion

Match each compound/ion's chemical behavior with the given properties/reactions by reviewing organic chemistry principles. For example, aldehydes, like \(\mathrm{C}_{6}\mathrm{H}_{5}\mathrm{CHO}\), react with 2,4-dinitrophenylhydrazine to give precipitates.

Combine Matches

Align the compounds/ions with their correct reactions/properties from the options given. This includes knowing that cyanide ions are involved in cyanohydrin formation, acetylene can react with \(\mathrm{AgNO}_{3}\) to form a precipitate, etc.

Fill in the ORS Matrix

Darken the appropriate bubbles in the \(4 \times 4\) matrix based on the matches made in the previous steps to complete the task.

Key concepts

Organic Chemistry Reactions

Organic chemistry is a sub-discipline of chemistry that deals with the structures, properties, and reactions of organic compounds, which contain carbon. It's a vast field with numerous reactions, each with its significance in both nature and industry.

One of the basic principles in understanding organic chemistry reactions is recognizing functional groups, which are specific groupings of atoms within molecules that have their own characteristic reactivity. For instance, aldehydes like \(\mathrm{C}_6\mathrm{H}_5\mathrm{CHO}\) possess a carbonyl group (a carbon double-bonded to oxygen) that makes them reactive towards reagents like 2,4-dinitrophenylhydrazine. This reagent forms a hydrazone when reacting with the carbonyl group, resulting in a precipitate, a solid material that emerges from a solution—a phenomenon that is useful for the identification and characterization of aldehydes. This is one way aldehydes can be distinguished from other functional groups in a mixture.

Understanding the varied reactivity of different functional groups allows chemists to predict and carry out a variety of organic transformations, essential for creating complex molecules in organic synthesis.

Nucleophilic Reactivity

Nucleophilic reactivity is a fundamental concept in organic chemistry. Nucleophiles are species rich in electrons and thus 'nucleus-loving'. They seek positively charged or electron-deficient regions in other molecules to donate their electrons. A common attribute of nucleophiles is their ability to form new bonds by attacking positive or partially positive atoms in other molecules, such as carbon atoms in carbonyl groups.

In organic reactions, nucleophiles are often involved in substitution or addition reactions. For example, iodide ions \(\mathrm{I}^{-}\) are good nucleophiles due to the presence of a lone pair of electrons that can be donated to form new bonds. This is why they are often seen in substitution reactions, where they 'replace' another atom or group in a molecule. Similarly, cyanide ions (CN^-) exhibit nucleophilic behavior by attacking electrophilic carbons, leading to the formation of cyanohydrins, compounds with a nitrile and hydroxyl group attached to the same carbon atom.

Understanding the reactivity of nucleophiles is crucial for predicting the outcome of many organic reactions, especially in designing synthetic pathways for complex organic compounds.

Chemical Properties Identification

Identifying the chemical properties of substances is a foundational skill in chemistry. Chemical properties describe a substance's ability to undergo a specific chemical change. They are distinct from physical properties, which can be observed without changing the substance's chemical identity, such as melting point, color, or density. Chemical properties include reactivity with other chemicals, acidity or basicity, stability, and many others.

For instance, acetylene \(\mathrm{CH}_3\mathrm{C}\equiv\mathrm{CH}\) can be identified by its reaction with silver nitrate (\(\mathrm{AgNO}_3\)), forming a precipitate. This is because the triple bond of acetylene reacts with silver ions to form a silver acetylide complex, a reaction specific to terminal alkynes. Such reactions are of practical importance in the field as they can be diagnostic; they help chemists confirm the presence of certain functional groups within a molecule.

Being able to identify chemical properties is crucial for chemists when analyzing compounds and developing synthetic methods. It's also valuable for students preparing for competitive exams like JEE Advanced Chemistry, where recognizing and correlating the chemical behavior of different substances with their potential reactions is a tested skill.