Context

Salt hydrolysis is a chemical process of dissociation or ionization that occurs when a salt is dissolved in water. In other words, it is the phenomenon by which salts, after being dissolved in water, hydrolyze their ions to form new substances. Understanding this concept is essential for understanding the chemistry of solutions, and more specifically, the chemistry of acidic and basic solutions.

In the process of salt hydrolysis, the dissolved salt originates a cation and an anion. The interaction with water can result in an acidic, basic, or neutral solution. Salt hydrolysis can be considered a reverse reaction of neutralization. Its nature depends on the ability of the cation and the anion to react with water to produce H+ (hydrogen) or OH- (hydroxyl) ions, thus originating acidic or basic solutions, respectively.

Thus, we can say that salt hydrolysis is a relevant topic for understanding the characteristics of solutions and how these properties influence the processes in which they are involved. For scientists, this understanding is crucial for predicting the behavior of certain compounds and their reactions.

Salt hydrolysis has a variety of practical applications in our daily lives and in industry. For example, household cleaning products, such as detergents, use the concept of salt hydrolysis. They contain salts of weak acids or weak bases which, when dissolved in water, undergo hydrolysis, producing a solution that helps remove dirt and grease.

Another important application is in the food industry. Controlling the pH of food is essential to prevent the proliferation of microorganisms and to maintain the organoleptic characteristics of the product. In this sense, salt hydrolysis is a process used to maintain the pH balance in food.

For the development of this project, it will be necessary to deepen the studies on the key theoretical concepts: Ionization, Salts, Acidic and Basic Properties, Salt Hydrolysis and pH.

Consider the following sources for your study:

1. CHEMISTRY - Volume 2 - Usberco and Salvador - Revised Edition 2017.
2. Website "Mundo Educação" - Chemistry Section.
3. YouTube Channel "Química em Ação" by Professor Paulo Valim.
4. Website "Brasil Escola" - Chemistry Section.

Practical Activity: "Salt, Water, and a Pinch of Chemistry: Exploring Salt Hydrolysis"

Project Objective:

This hands-on activity aims to deepen students' understanding of salt hydrolysis, and how cations and anions react with water to form acidic, basic, or neutral solutions. In addition, students are expected to develop teamwork skills, effective communication, and time management.

Detailed Project Description:

This project requires that each group of 3 to 5 students plan and execute an experiment to investigate the reaction of different salts with water, i.e., to perform salt hydrolysis. Each group must select three different salts to test, document each step of the experiment, and collect the necessary data to analyze the acidity or basicity of the resulting solution of each salt, using appropriate pH indicators. In addition, students should investigate and discuss the practical applications of salt hydrolysis in everyday life and industry.

Required Materials:

1. Three different types of salts (The salts should be chosen by the students based on the research they will do during the development of the project.)
2. Distilled water
3. Beakers
4. Glass rods
5. pH indicators (pH indicator paper, phenolphthalein solution, etc.)
6. Safety gloves
7. Safety glasses

Detailed Step-by-Step Instructions for the Activity:

1. Research the available salts and select three for the experiment. Justify your choice based on the properties of each one.
2. Plan the experiment: how the salts will be dissolved, in what sequence, how the pH will be measured, etc.
3. Prepare the experiment environment following the laboratory safety rules.
4. Dissolve each of the selected salts in distilled water in separate beakers.
5. After the salts are completely dissolved, use the pH indicators to measure the acidity or basicity of the solution.
6. Document all steps, observations, and measurements.
7. Analyze the results obtained and draw conclusions.
8. Prepare a final report detailing the entire project.

Project Deliverables:

A research plan, experiment records, and a final report must be submitted at the end of the project. The final report should include:

1. Introduction: Contextualization of the topic, its relevance, practical applications, and the objective of the project.
2. Development: Explanation of the theory behind the project's central themes, detailing the activity, methodology used, presentation, and discussion of the results obtained.
3. Conclusions: Summary of the main points, explanation of the lessons learned, conclusions drawn about the project, and reflections on the teamwork process.
4. Bibliography: Sources used for the project, such as books, web pages, videos, etc.

This project requires more than 12 hours of work per student and integrates the topics of Ionization, Salts, Acidic and Basic Properties, Salt Hydrolysis, and pH. The project also integrates technical and socio-emotional skills, including time management, communication, problem solving, creative thinking, and proactivity.