Identify the arrows shown by type and predict the product that should result.
(a)

Verified step by step guidance

1. Step 1: Analyze the reaction mechanism. The image shows a benzene ring reacting with bromine (Br₂) in the presence of an arrow indicating electron movement. The curved arrows represent the movement of electrons during the reaction.
2. Step 2: Identify the type of arrows. The first arrow originates from the π-electrons of the benzene ring and points toward one bromine atom in the Br₂ molecule. This indicates an electrophilic aromatic substitution reaction, where the π-electrons attack the bromine molecule.
3. Step 3: Predict the intermediate. When the π-electrons attack Br₂, one bromine atom becomes attached to the benzene ring, forming a bromonium ion intermediate. The other bromine atom becomes a bromide ion (Br⁻).
4. Step 4: Consider the role of the bromide ion. The bromide ion (Br⁻) acts as a nucleophile and removes a hydrogen atom from the benzene ring, restoring aromaticity to the ring.
5. Step 5: Predict the final product. The final product is bromobenzene, where one hydrogen atom on the benzene ring is replaced by a bromine atom. This is a classic example of electrophilic aromatic substitution.

Key Concepts

Reaction Mechanisms

Understanding reaction mechanisms is crucial in organic chemistry as they describe the step-by-step process by which reactants transform into products. This includes identifying the movement of electrons, the formation and breaking of bonds, and the role of intermediates. Recognizing the type of mechanism (e.g., nucleophilic substitution, elimination) helps predict the products formed in a reaction.

Arrow Notation

Arrow notation is a visual representation used in organic chemistry to indicate the movement of electrons during chemical reactions. Different types of arrows signify different actions: a single-headed arrow shows the movement of one electron, while a double-headed arrow indicates the movement of a pair of electrons. Understanding these notations is essential for interpreting reaction mechanisms and predicting products.

Functional Groups

Functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. Identifying functional groups in reactants is key to predicting the outcome of a reaction, as they dictate reactivity and the types of products formed. Familiarity with common functional groups, such as alcohols, amines, and carboxylic acids, is essential for understanding organic reactions.