Question

Write the structure of benzylamine hydrochloride in two different ways, and name the hydrochloride as an ammonium salt.

Short answer

Benzylamine hydrochloride can be structured as \( C_6H_5CH_2NH_3^+Cl^- \) and named benzylammonium chloride.

Step-by-step solution

Understand Benzylamine

Benzylamine is an organic compound with the chemical formula \( C_6H_5CH_2NH_2 \). It consists of a benzene ring attached to a CH2 group, which is further attached to an amino group (NH2).

Structure of Benzylamine Hydrochloride

To form benzylamine hydrochloride, benzylamine reacts with hydrochloric acid (HCl). The amino group (NH2) in benzylamine accepts a proton (H+) from HCl and becomes NH3+, forming the structure \( C_6H_5CH_2NH_3^+Cl^- \). This creates a salt where the nitrogen atom carries a positive charge and a chloride ion is present as a counterion.

Drawing the Ionic Structure

The ionic structure of benzylamine hydrochloride can be drawn as follows:- The benzene ring \( C_6H_5 \) remains intact.- The CH2 group connects the benzene ring and the ammonium ion \( NH_3^+ \).- A chloride ion \( Cl^- \) is present, balancing the positive charge of the ammonium ion.

Alternative Representation

The structure can also be shown as ionic pairs, specifically emphasizing the ionic character:- One structure is \( C_6H_5CH_2NH_3^+ \) and the other is \( Cl^- \).This highlights the ammonium cation and chloride anion form of the compound.

Naming as Ammonium Salt

When naming benzylamine hydrochloride as an ammonium salt, it can be referred to as benzylammonium chloride. Naming priorities consider the ammonium ion formed after protonation.

Key concepts

Organic Compound

Organic compounds are vital in chemistry as they primarily consist of carbon atoms. These compounds can also contain hydrogen, oxygen, nitrogen, and other elements, but carbon-hydrogen bonds are the hallmark of organic molecules.
In the case of benzylamine, it falls under the category of organic compounds because it includes a benzene ring—recognized for its carbon-rich and stable aromatic structure. This aromatic ring influences both the chemical and physical properties of benzylamine.
Benzylamine is a simple amine, containing an amino group (NH2) connected directly to a benzyl group (C6H5CH2). This arrangement gives benzylamine the formula C6H5CH2NH2, illustrating how organic compounds maintain their complexity with even relatively simple structures.

• Characteristic functional groups: These are specific groups of atoms responsible for the characteristic reactions of organic compounds. In benzylamine, the key functional group is the amino group.
• Benzene ring: The core of many aromatic organic compounds, providing stability and unique reactivity.

These features are essential for recognizing and predicting the behavior of organic compounds in various chemical reactions.

Chemical Formula

The chemical formula of a compound is a shorthand representation showing the elements it contains and their respective proportions. For organic compounds like benzylamine, the formula helps convey essential structural information succinctly.
The chemical formula for benzylamine is C6H5CH2NH2. This notation breaks down as follows:

• C6H5: Represents the benzene ring, accounting for six carbon atoms and five hydrogen atoms.
• CH2: This is the methylene bridge connecting the benzene ring with the amino group.
• NH2: This stands for the amino group, a crucial functional group in many nitrogen-containing organic compounds.

When benzylamine reacts with hydrochloric acid, it forms benzylamine hydrochloride. The chemical formula changes due to the interaction with HCl, forming C6H5CH2NH3^+Cl^-.

• The benzylamine part C6H5CH2NH2 receives a proton (H+) from HCl, forming NH3^+.
• Cl^- represents the chloride ion, balancing the positive charge on the nitrogen atom.

This new arrangement is essential for understanding the transformed properties and reactivity of benzylamine in its hydrochloride form.

Ammonium Salt

An ammonium salt is formed when an amine, like benzylamine, reacts with an acid such as hydrochloric acid. In this reaction, the amine group (NH2) accepts a hydrogen ion (H+), attributed to its basic nature, and transforms into an ammonium ion.
In benzylamine hydrochloride, the NH2 group becomes an NH3^+ group, forming the ammonium cation in the compound. This cation pairs with the chloride ion (Cl^-) resulting from dissociation of hydrochloric acid to form the salt commonly referred to as benzylammonium chloride.
Ammonium salts like benzylammonium chloride are characterized by the following:

• Proton acceptance: The amine group gains a proton, forming an ammonium ion, which is the core feature that transitions it to an ammonium salt.
• Balancing ion: A negatively charged ion, in this case, Cl^-, is associated to maintain electrical neutrality.
• Neutralization reaction: The amine acts as a base, reacting with the acid (HCl) to form the salt, neutralizing the acid in the process.

Recognizing these aspects of ammonium salts helps in understanding the behavior and uses of compounds like benzylamine hydrochloride in various applications, ranging from pharmaceuticals to industrial processes.