Write a balanced net ionic equation for the reaction of each of the following ions with water. In each case, identify the Brønsted–Lowry acids and bases and the conjugate acid– base pairs. (a) CH3NH3+

Verified step by step guidance

1. Identify the species involved in the reaction: \( \text{CH}_3\text{NH}_3^+ \) and water (\( \text{H}_2\text{O} \)).
2. Recognize that \( \text{CH}_3\text{NH}_3^+ \) is the conjugate acid of the weak base \( \text{CH}_3\text{NH}_2 \).
3. Write the chemical equation for the reaction: \( \text{CH}_3\text{NH}_3^+ + \text{H}_2\text{O} \rightarrow \text{CH}_3\text{NH}_2 + \text{H}_3\text{O}^+ \).
4. Identify the Brønsted–Lowry acids and bases: \( \text{CH}_3\text{NH}_3^+ \) is the acid donating a proton, and \( \text{H}_2\text{O} \) is the base accepting a proton.
5. Determine the conjugate acid-base pairs: \( \text{CH}_3\text{NH}_3^+ \) and \( \text{CH}_3\text{NH}_2 \) form one pair, while \( \text{H}_2\text{O} \) and \( \text{H}_3\text{O}^+ \) form the other pair.

Key Concepts

Net Ionic Equations

A net ionic equation represents the chemical species that are involved in a reaction, excluding spectator ions. It focuses on the ions and molecules that undergo a change during the reaction, providing a clearer picture of the chemical processes. In the case of reactions involving water, it highlights the interaction between ions and water molecules, showing how they donate or accept protons.

Brønsted–Lowry Acids and Bases

The Brønsted–Lowry theory defines acids as proton donors and bases as proton acceptors. This framework allows for the identification of acid-base reactions based on the transfer of protons (H+ ions). In the context of the given question, recognizing CH3NH3+ as a Brønsted–Lowry acid helps in determining its behavior in water and the resulting conjugate base.

Conjugate Acid-Base Pairs

Conjugate acid-base pairs consist of two species that differ by the presence of a proton. When an acid donates a proton, it forms its conjugate base, while a base that accepts a proton becomes its conjugate acid. Understanding these pairs is essential for analyzing the equilibrium of acid-base reactions and predicting the direction of the reaction in the context of the net ionic equation.