Question

Which one of the following compounds liberates \(\mathrm{CO}_{2}\) from aqueous \(\mathrm{NaHCO}_{3} ?\) (a) \(\mathrm{CHCl}_{3}\) (b) \(\mathrm{CH}_{3} \mathrm{Cl}\) (c) Anilinium chloride (d) \(\mathrm{CCl}_{4}\)

Short answer

Anilinium chloride liberates CO2 from NaHCO3.

Step-by-step solution

Understand the Reaction with NaHCO3

NaHCO3 (sodium bicarbonate) reacts with acids to release CO2 gas. This is a characteristic reaction of bicarbonate with acids.

Analyze the Compounds

Evaluate each option to determine which one is capable of providing hydrogen ions (H+) to react with NaHCO3, thus liberating CO2. - (a) CHCl3 (Chloroform): Does not have acidic properties. - (b) CH3Cl (Methyl chloride): Does not have acidic properties. - (c) Anilinium chloride: It is a salt of anilinium ion (a weak acid). - (d) CCl4 (Carbon tetrachloride): Does not have acidic properties.

Determine the Acidic Compound

Evaluate the compound that can act as a proton donor in an aqueous solution. Anilinium chloride (c) can donate protons in water due to the presence of the anilinium ion (C6H5NH3+), which can react with NaHCO3 to release CO2.

Key concepts

Understanding Acid-Base Reactions

Acid-base reactions are fundamental in chemistry and involve the transfer of protons (H⁺ ions) between substances. An acid is a molecule that can donate a proton, while a base accepts a proton. This interaction is crucial for many everyday processes.
For example, when an acid reacts with a base, they often neutralize each other, forming water and a salt. But another fascinating reaction involves the release of gases. This occurs, for instance, when acids react with bicarbonates like sodium bicarbonate (NaHCO₃). In such cases, carbon dioxide (\( \mathrm{CO}_{2}\)) gas is often liberated.
In the original exercise, the reaction hinges on finding the substance among the given options that can donate a proton, reacting with sodium bicarbonate to form water, a salt, and release carbon dioxide. This is a classic example of an acid-base reaction in action.

Exploring Sodium Bicarbonate

Sodium bicarbonate, commonly known as baking soda, is a remarkable compound with diverse applications. While it's best known for its baking properties, it also plays a vital role in chemical reactions.
NaHCO₃ is a weak base. Its ability to react with acids to liberate carbon dioxide gas is a key feature. This reaction is not just central to cooking, where it's used to make dough rise, but also in environmental applications, such as neutralizing acids in lakes and streams.
When thinking about sodium bicarbonate's interactions, remember:

• It forms carbon dioxide gas, a characteristic used in many practical applications.
• Bicarbonate ions (HCO₃⁻) react readily with H⁺ ions from acids.
• This reaction is efficient in solutions where acidic conditions are present.

Understanding these points can help you see why sodium bicarbonate is the go-to for reactions needing to remove CO₂ from solutions.

The Nature of Compound Acidity

Acidity in compounds is determined by their ability to donate a proton in solution. Not all compounds exhibit acidity. It depends on their structure and the presence of acidic hydrogen atoms.
In the context of the original exercise, it's essential to identify compounds that can release ions in aqueous environments. The compound that stands out is anilinium chloride. This salt releases anilinium ions (C₆H₅NH₃⁺) which are capable of donating protons indirectly due to their natural dissociation.
To understand why only certain compounds are acidic enough to react with sodium bicarbonate, remember:

• Acids need to have easily removable hydrogen atoms.
• Environmental factors such as the solvent can impact acidity.
• Structural features like polar bonds often indicate acidity.

Examining these characteristics will help you determine why some compounds are considered acidic while others, like chloroform or carbon tetrachloride, are not. This specificity is crucial in predicting reactions and understanding their outcomes.