Question

Statement - 1: When \(\mathrm{NH}_{2}-\mathrm{NH}-\mathrm{C}-\mathrm{NH}_{2}\) is \(\mathrm{NH}_{2}-\mathrm{NH}-\mathrm{C}-\mathrm{NH}_{2}\) is reacted with will react with acetaldehyde to form major product. Statement - 2: In the above reaction, pH range is maintained between \(4.5\) to \(6.0\). (A) Both statements are correct and statement- 2 is correct explanation of statement-1. (B) Both statements are correct and statement- 2 is not correct explanation of statement-1. (C) Statement- 1 is correct but statement- 2 is wrong statement. (D) Statement- 1 is wrong but statement- 2 is correct statement.

Short answer

Answer: \( (A) \) Both statements are correct and Statement-2 is the correct explanation of Statement-1.

Step-by-step solution

Identify the reactants

The reactants in this reaction are: 1. Hydrazine: \(\mathrm{NH}_{2}-\mathrm{NH}-\mathrm{C}-\mathrm{NH}_{2}\) 2. Acetaldehyde: \(\mathrm{CH}_{3}\mathrm{CHO}\)

Write the reaction

The reaction between hydrazine and acetaldehyde forms a product through a process called the Wolff-Kishner reduction: \(\mathrm{NH}_{2}-\mathrm{NH}-\mathrm{C}-\mathrm{NH}_{2} + \mathrm{CH}_{3}\mathrm{CHO} \rightarrow \mathrm{NH}_{2}-\mathrm{NH}-\mathrm{C}-\mathrm{NH}(CH_{3})\)

Check Statement-1

Statement-1 is correct. The major product when \(\mathrm{NH}_{2}-\mathrm{NH}-\mathrm{C}-\mathrm{NH}_{2}\) reacts with acetaldehyde is indeed \(\mathrm{NH}_{2}-\mathrm{NH}-\mathrm{C}-\mathrm{NH}(CH_{3})\).

Check the pH range

The pH range of 4.5 to 6.0 is typically maintained during the Wolff-Kishner reduction. This is to ensure that the reaction proceeds through the correct pathway, towards the desired product, and to avoid unwanted side reactions.

Check Statement-2

Statement-2 is correct. The pH range between 4.5 and 6.0 is maintained throughout the reaction.

Determine the relationship

Statement-2 provides the correct explanation for Statement-1, since maintaining the pH range of 4.5 to 6.0 ensures that the major product is formed correctly. So, the answer is (A) Both statements are correct and Statement-2 is the correct explanation of Statement-1.

Key concepts

Understanding Organic Reaction Mechanisms

Organic reaction mechanisms are essential in understanding how chemical reactions proceed. They provide a roadmap of how bonds break and form during a reaction. The Wolff-Kishner reduction is a type of organic reaction mechanism that involves the reduction of a carbonyl group to a methylene group. During this process, hydrazine (\(\mathrm{NH}_{2}-\mathrm{NH}-\mathrm{C}-\mathrm{NH}_{2}\)) plays a crucial role, undergoing several intermediate steps before reaching the final product.

This reaction generally requires specific conditions, such as the right pH balance, to ensure that the transformation occurs smoothly. During the reaction, intermediates form and decompose, releasing nitrogen gas and leading to the product formation. It's a prime example of how understanding the step-by-step breakdown of a reaction can highlight the importance of each step in ensuring the desired outcome.

In summary, understanding any organic reaction mechanism requires breaking it down into its core steps and analyzing each part's contribution to the overall transformation.

Insights into Hydrazine Chemistry

Hydrazine, \(\mathrm{NH}_{2}-\mathrm{NH}_{2}\), is a bifunctional molecule often used in reduction reactions. In the Wolff-Kishner reduction, hydrazine acts as the reducing agent. It plays a pivotal role in converting carbonyl groups, such as those found in aldehydes and ketones, into methylene groups.

Hydrazine undergoes a significant transformation during these reactions. It reacts with the carbonyl compound to form a hydrazone intermediate. This intermediate is essential as it sets the stage for the release of nitrogen gas, a step that drives the reaction forward to completion. The ability to harness such unique properties highlights the value of hydrazine in organic chemistry.

• Acts as a reducing agent
• Forms key intermediates
• Promotes completion by releasing nitrogen gas

Understanding hydrazine chemistry is crucial in grasping why certain reaction conditions, like temperature and pH, must be controlled for the reaction to succeed.

Importance of Reaction Conditions and pH

The success of the Wolff-Kishner reduction depends significantly on controlled reaction conditions, particularly the pH level. Maintaining a pH between 4.5 to 6.0 is critical. It helps ensure the reaction progresses through the right pathways and minimizes the formation of unwanted by-products.

Reaction conditions such as pH affect the stability of intermediates and the overall rate of the reaction. A slight deviation from the optimal pH could result in the reaction stopping prematurely or the formation of side products, which decreases the yield of the desired compound.

• Ensures proper reaction pathway
• Reduces by-product formation
• Optimizes product yield

Thus, controlling the pH within the specific range is vital for efficiently executing the Wolff-Kishner reduction, demonstrating how sensitivity to reaction conditions can substantially impact the outcome of the chemical process.