The element bromine was first prepared by oxidation of aqueous potassium bromide with solid manganese(IV) oxide. Write a balanced net ionic equation for the reaction in an aqueous acidic solution. Mn2+ is also formed.

Name: Chemistry
Author: McMurry
ISBN: 9781292336145

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Identify the reactants and products in the reaction: Potassium bromide (KBr) and manganese(IV) oxide (MnO2) are the reactants, while bromine (Br2) and Mn2+ are the products.

Write the half-reaction for the oxidation of bromide ions (Br-) to bromine (Br2). In acidic solution, this involves the loss of electrons by bromide ions.

Write the half-reaction for the reduction of manganese(IV) oxide (MnO2) to Mn2+. In acidic solution, this involves the gain of electrons by MnO2.

Balance each half-reaction for mass and charge. This includes balancing the atoms other than O and H first, then balancing O atoms by adding H2O, H atoms by adding H+, and finally balancing the charge by adding electrons.

Combine the balanced half-reactions to form the overall balanced net ionic equation, ensuring that the electrons lost in the oxidation half-reaction equal the electrons gained in the reduction half-reaction.

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Oxidation-Reduction Reactions

Oxidation-reduction (redox) reactions involve the transfer of electrons between species, resulting in changes in oxidation states. In this context, manganese(IV) oxide acts as an oxidizing agent, facilitating the oxidation of bromide ions (Br-) to bromine (Br2), while itself being reduced to manganese(II) ions (Mn2+). Understanding these processes is crucial for writing balanced equations.

Net Ionic Equations

A net ionic equation represents the actual chemical species participating in a reaction, excluding spectator ions that do not change during the reaction. To write a net ionic equation, one must first identify the ions in solution, eliminate the spectator ions, and ensure that both mass and charge are balanced. This simplification helps focus on the key chemical changes occurring in the reaction.

Acidic Aqueous Solutions

In an acidic aqueous solution, the presence of hydrogen ions (H+) influences the behavior of reactants and products. Acidic conditions can affect the solubility and reactivity of certain species, and they often facilitate the transfer of protons in redox reactions. Recognizing the role of acidity is essential for accurately balancing the net ionic equation and understanding the reaction dynamics.