Problem 56 - 43 Years JEE ADVANCED (1978-2020) + JEE MAIN Chapterwise & Topicwise Solved Papers Chemistry

Question

Each item from (i) to (x) given below indicates a reaction type, a process or a homologue. Match each of these items with the related phrase by writing the correct phrase in the corresponding vacant space given under each. The correct phrase must be picked only from those given below within brackets: (Bayer's process, Nucleophilic addition, Free radical substitution, Ostwald's process, Homologous pair, Cyanamide process, Electrophilic substitution, Homolytic addition, Thermite process, Nucleophilic substitution)

Step-by-Step Solution

Answer

Match each listed item with its related process or reaction type, using the provided phrases.

Step 1: Analyze Reaction Processes

First, identify the items from (i) to (x) which are related to reactions or processes based on chemical knowledge. For example, recognize that 'Bayer's process' is used for extracting aluminum.

Step 2: Identify Process Phrases

Pair each identified reaction or process from (i) to (x) with the matching phrase provided in the list. For instance, recognize that 'Cyanamide process' is a method used for producing urea.

Step 3: Recognize Reaction Types

Identify any reactions among the items, such as 'Nucleophilic addition,' 'Free radical substitution,' and determine their matching phrases.

Step 4: Homologue Pairing

Identify homologous pairings from the items given and match them with the appropriate phrase, like matching a 'Homologous pair' from the list.

Step 5: Finalize Matching

Write down the final matches for each item from (i) to (x) with their corresponding phrases from the options provided, ensuring each item is connected with the correct type or process.

Key Concepts

Reaction Processes

Chemical reactions are vital processes that transform substances into different entities. They are characterized by a variety of different mechanisms, known as reaction processes. Each process involves unique steps and conditions.
Some common reaction processes include:

• Bayer's process: A method used to extract aluminum from bauxite ore through chemical and physical transformations.
• Ostwald's process: A method to produce nitric acid by oxidizing ammonia and reacting it with water.
• Thermite process: A type of aluminothermic reaction used in welding to produce intense heat.

Reaction processes are fundamental in fields such as industrial chemistry, where large-scale production of chemicals is necessary. Each process is designed to maximize efficiency and yield of the desired product.

Homologue Pair

In chemistry, a homologue pair refers to molecules that are part of a homologous series, differing by a specific structural unit, typically a methylene (-CH₂-) group.
These pairs share similar chemical properties but exhibit gradual physical property variations, such as boiling point.

• For example, methane (CH₄) and ethane (C₂H₆) are homologous pairs, sharing common functional characteristics of alkanes.
• Their series follows a general formula represented by C_nH_2n+2 for alkanes.

Understanding homologue pairs helps in predicting the behavior of chemicals in the same series, which is useful for constructing more complex molecules in synthetic chemistry.

Nucleophilic Reaction

Nucleophilic reactions are a type of chemical reaction where an electron-rich species, called a nucleophile, donates an electron pair to an electron-deficient species, known as an electrophile.
These reactions can occur as additions, where the nucleophile adds to a substrate, or as substitutions, where a nucleophile replaces a leaving group on the substrate.

• A classic example is the nucleophilic substitution (\(S_N1\) or \(S_N2\)) reaction, where a nucleophile targets a carbon atom attached to a leaving group, resulting in the leaving group being replaced.
• In \(S_N2\) reactions, the nucleophile attacks the substrate's rear, leading to an inversion of configuration.

These reactions are pivotal in organic chemistry, allowing the construction of a wide variety of chemical compounds by modifying existing molecular frameworks.

Electrophilic Reaction

Electrophilic reactions involve electron-poor species, or electrophiles, which accept electron pairs from electron-rich nucleophiles.
These reactions are common in organic chemistry, particularly in the formation of covalent bonds.

• Electrophilic substitution reactions occur frequently in aromatic compounds where an electrophile replaces a hydrogen on the aromatic ring.
• A well-known example is the nitration of benzene, where nitric acid reacts with benzene in the presence of sulfuric acid to introduce a nitro group.

Electrophilic reactions are essential for forming aromatic ring functionalizations and creating a variety of substituted aromatic compounds, widely used in the pharmaceutical industry.