Chapter 12: Problem 81
Which of the following compounds does not dissolve in concentrated \(\mathrm{H}_{2} \mathrm{SO}_{4}\) even on warming? (a) Aniline (b) Benzene (c) Ethylene (d) Hexane
Short Answer
Expert verified
Benzene does not dissolve in concentrated Sm{H}{2} b{SO}{4} .
Step by step solution
01
Understanding the Nature of [1mlConcentrated [ Ulphuric Acid
Concentrated sulfuric acid ( Sm{H}{2} b{SO}{4} ) is a strong acid known for its ability to protonate compounds and act as a dehydrating agent. It generally interacts with polar compounds and those containing functional groups that can be protonated.
02
Analyzing Aniline's Solubility
Aniline, being a basic compound, can form salts with Sm{H}{2} b{SO}{4} , which makes it soluble. The nitrogen in aniline can accept a proton from Sm{H}{2} b{SO}{4} , enhancing its solubility.
03
Evaluating Benzene's Behavior
Benzene is a non-polar aromatic compound with no functional groups to react with or dissolve in concentrated Sm{H}{2} b{SO}{4} . Its structure does not allow it to interact significantly with sulfuric acid.
04
Considering Ethylene's Interaction
Ethylene is an alkene and can react with Sm{H}{2} b{SO}{4} , as it may protonate the double bond in ethylene, forming a carbocation that increases solubility.
05
Exploring Hexane's Solubility
Hexane is a non-polar alkane with no sites for protonation or interaction with Sm{H}{2} b{SO}{4} , similar to benzene. It does not dissolve in concentrated sulfuric acid.
06
Identifying the Outlier
From the analysis, benzene and hexane are non-polar and do not dissolve in Sm{H}{2} b{SO}{4} . However, the question emphasizes solubility, and benzene is widely recognized for its resistance to dissolving in concentrated Sm{H}{2} b{SO}{4} compared to the interactions of the other compounds.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Sulfuric Acid Properties
Sulfuric acid (\(\mathrm{H}_{2} \mathrm{SO}_{4}\)) is one of the most important industrial chemicals. It is a strong acid, known for its corrosive properties and ability to donate protons to other substances. This characteristic makes it a powerful protonating agent. In fact, sulfuric acid can dehydrate and oxidize organic compounds due to its strong acidic nature.
When concentrated, sulfuric acid is a thick, oily liquid, appearing colorless to slightly yellowish, and its ability to ingest water from other substances is remarkable. This dehydrating feature is often applied in chemical reactions to remove water and drive equilibrium towards product formation. Chemically, it is also favored for its exothermic reaction when mixed with water, releasing substantial heat.
Applications of sulfuric acid include its use in the production of fertilizers, explosives, and various chemicals. Moreover, its role in acid-base titrations is essential for determining the concentrations of basic solutions.
When concentrated, sulfuric acid is a thick, oily liquid, appearing colorless to slightly yellowish, and its ability to ingest water from other substances is remarkable. This dehydrating feature is often applied in chemical reactions to remove water and drive equilibrium towards product formation. Chemically, it is also favored for its exothermic reaction when mixed with water, releasing substantial heat.
Applications of sulfuric acid include its use in the production of fertilizers, explosives, and various chemicals. Moreover, its role in acid-base titrations is essential for determining the concentrations of basic solutions.
Solubility of Organic Compounds
Solubility determines how substances dissolve in solvents, such as sulfuric acid. Organic compounds vary in solubility based on their structure and functional groups. Generally, polar organic compounds or those with functional groups that can form hydrogen bonds dissolve more readily in polar solvents like \(\mathrm{H}_{2} \mathrm{SO}_{4}\).
For a compound to dissolve in concentrated sulfuric acid, it should ideally have functional groups capable of protonation or hydrogen bonding. Compounds such as aniline, which is basic, can accept protons from the acid, forming soluble salts. Meanwhile, aliphatic alkanes, which have no polar sites, remain insoluble.
Typically, the solubility of organic compounds is guided by the principle "like dissolves like," meaning polar solvents dissolve polar compounds, while non-polar solvents are best for non-polar compounds.
For a compound to dissolve in concentrated sulfuric acid, it should ideally have functional groups capable of protonation or hydrogen bonding. Compounds such as aniline, which is basic, can accept protons from the acid, forming soluble salts. Meanwhile, aliphatic alkanes, which have no polar sites, remain insoluble.
Typically, the solubility of organic compounds is guided by the principle "like dissolves like," meaning polar solvents dissolve polar compounds, while non-polar solvents are best for non-polar compounds.
Polar and Non-Polar Compounds
Organic compounds are distinguished by their polarity, which affects solubility and chemical behavior. Polar compounds have an uneven distribution of electron density, leading to partial positive and negative charges across the molecule. These charges enable interactions with polar solvents.
Non-polar compounds, on the other hand, have a uniform electron distribution, resulting in no net dipole moment. Such compounds typically dissolve in non-polar solvents like hexane or benzene, rather than polar solvents like \(\mathrm{H}_{2} \mathrm{SO}_{4}\).
For example, benzene and hexane, both non-polar, lack functional groups capable of forming strong interactions with water or sulfuric acid. Their solubility remains limited in such polar environments, demonstrating their chemical inertness when faced with polar molecules.
Non-polar compounds, on the other hand, have a uniform electron distribution, resulting in no net dipole moment. Such compounds typically dissolve in non-polar solvents like hexane or benzene, rather than polar solvents like \(\mathrm{H}_{2} \mathrm{SO}_{4}\).
For example, benzene and hexane, both non-polar, lack functional groups capable of forming strong interactions with water or sulfuric acid. Their solubility remains limited in such polar environments, demonstrating their chemical inertness when faced with polar molecules.
Acid-Base Reactions
Acid-base reactions are fundamental in chemistry, involving the transfer of protons from acids to bases. Sulfuric acid, being a strong acid, readily donates protons to bases. These reactions often produce salt and water, and they are essential to various chemical processes.
When an organic compound acts as a base, like aniline, it can accept a proton from sulfuric acid, forming a protonated species. This protonation increases the compound's solubility in \(\mathrm{H}_{2} \mathrm{SO}_{4}\), highlighting the role of acidity in solubility.
Alkenes, such as ethylene, can undergo acid-catalyzed additions by forming carbocations upon protonation. These interactions are crucial in petrochemical industries, where transformations of simple compounds into more complex forms are necessary. Acid-base reactions thus play a crucial role in understanding solubility and the reactivity of organic molecules in the presence of acids.
When an organic compound acts as a base, like aniline, it can accept a proton from sulfuric acid, forming a protonated species. This protonation increases the compound's solubility in \(\mathrm{H}_{2} \mathrm{SO}_{4}\), highlighting the role of acidity in solubility.
Alkenes, such as ethylene, can undergo acid-catalyzed additions by forming carbocations upon protonation. These interactions are crucial in petrochemical industries, where transformations of simple compounds into more complex forms are necessary. Acid-base reactions thus play a crucial role in understanding solubility and the reactivity of organic molecules in the presence of acids.
