Question

In laboratory preparation of Acetone Xis (A) Anhydrous acetone (B) Hydrated acetone (C) Sodium bisulphite adduct (D) None

Short answer

The correct answer is (C) Sodium bisulphite adduct. It is used in the purification step during the laboratory preparation of acetone, while other options refer to the types or properties of acetone but do not involve the preparation process.

Step-by-step solution

Review option A: Anhydrous acetone

Anhydrous acetone is simply acetone without any water content. Acetone (CH₃COCH₃) is a volatile, flammable, and versatile solvent used in laboratories. It is important to note that the question is about the laboratory preparation of acetone, not the identity of acetone itself.

Review option B: Hydrated acetone

Hydrated acetone would contain some water content mixed with acetone. However, again, this option does not provide information about a preparation method or a substance directly involved in the synthesis of acetone.

Review option C: Sodium bisulphite adduct

Sodium bisulfite adduct (NaHSO₃CH₃COCH₃) is formed when acetone reacts with sodium bisulfite (NaHSO₃). Sodium bisulfite adduct can be used as a method for purifying acetone by exploiting the difference in solubility between the adduct and the impurities in acetone, which is often an important step in the laboratory preparation of acetone.

Review option D: None

This option implies that none of the given options are involved in the laboratory preparation of acetone. We have to carefully analyze all other options and rule them out before choosing this option.

Conclusion

After reviewing all the options, we can conclude that Sodium bisulfite adduct (Option C) is the correct answer, as it is directly involved in the purification step in the laboratory preparation of acetone. The other options refer to the types or properties of acetone but do not involve the preparation process.

Key concepts

Acetone Purification

In the laboratory, one of the primary goals during the preparation of acetone is to ensure its purity. This process is essential because impurities can significantly affect the performance of acetone as a solvent in chemical reactions or other applications. Purification of acetone involves removing these impurities to achieve an anhydrous state, where no water content is present.
One common method of purification is distillation, which leverages acetone's volatility. By boiling the substance and re-condensing the vapor, it is possible to separate acetone from less volatile impurities. Another technique involves using sodium bisulfite adduct formation, which we will explore further in the next section.
The final, purified acetone must be clear and free of any residues or foreign substances. Quality control may involve testing for the presence of water or other contaminants using various methods, such as gas chromatography. Through these purification steps, acetone is made suitable for precise laboratory work.

Sodium Bisulfite Adduct

The sodium bisulfite adduct is an essential concept in the purification of acetone. Formed by the reaction between acetone (CH₃COCH₃) and sodium bisulfite (NaHSO₃), this adduct is a crystalline compound that is less soluble in organic solvents, allowing for practical separation techniques in laboratory settings.
Here's how it works: when acetone reacts with sodium bisulfite, it forms a solid that can be easily filtered out from the liquid phase. This crystalline adduct effectively separates acetone from impurities that remain dissolved in the solution. Following this separation, the compound can be decomposed, typically by adding an acid such as hydrochloric acid, to regenerate purified acetone.
This method highlights the importance of understanding chemical reactions and solubility principles in separation processes. By utilizing the sodium bisulfite adduct formation, chemists can efficiently purify acetone for experimental use.

Organic Chemistry Problem Solving

Problem solving in organic chemistry often involves applying theoretical knowledge to practical situations, such as in the preparation and purification of compounds like acetone. When approaching a problem like the one presented, it is crucial to follow several steps:

• First, clearly understand the question or problem statement. Identify what is being asked and what information is provided.
• Next, analyze each option given and determine its relevance to the problem based on known chemical principles and reactions.
• Engage in critical thinking to weigh each possibility and rule out incorrect or irrelevant options based on scientific reasoning.

This methodical approach helps build essential skills in organic chemistry, reinforcing concepts like reaction mechanisms, purification techniques, and more. Additionally, practical questions like these prepare students for real-world laboratory challenges.

Volatile Solvents

Acetone is an excellent example of a volatile solvent, which is defined by its ability to evaporate rapidly at room temperature due to a high vapor pressure and low boiling point. This property makes volatile solvents invaluable in a variety of applications, particularly in cleaning and degreasing processes in labs.
Volatile solvents like acetone are also key in the extraction and purification of compounds. Because they evaporate easily, they can be removed from a mixture by simple heating, leaving behind non-volatile substances.
However, handling volatile solvents must be done with caution due to their flammable nature and possible health implications. Proper ventilation and storage are critical in preventing the buildup of vapors, which could create explosive environments. Understanding the properties of volatile solvents helps chemists safely manipulate them for effective laboratory use.