📖 Lesson 1: Introduction to Acids, Bases, and Salts

👩🏽‍🏫 Introduction

Hello there, brilliant scientist! 👋🏽

Have you ever tasted lemon juice or soap by mistake? 🍋🧼 Lemon juice tastes sour, while soap tastes bitter and slippery. Did you ever wonder why? These are everyday examples of acids and bases at work! In this lesson, you’ll embark on an exciting journey into the fascinating world of acids, bases, and salts. These substances are more than just science terms; they are key players in your daily life, from cooking food to cleaning your home and even digesting your meals!

By the end of this lesson, you’ll clearly understand what acids, bases, and salts are, and why learning about them matters to you and your environment.

📘 Core Concepts

🔹 What are Acids?

Acids are substances that release hydrogen ions (H⁺) when dissolved in water. They have certain common properties:

• Taste sour (like lemon juice).

• Turn blue litmus paper red.

• React with metals like zinc to produce hydrogen gas (H₂).

Examples of common acids include:

• Citric acid (found in oranges and lemons).

• Hydrochloric acid (HCl) found in your stomach.

🔹 What are Bases?

Bases are substances that release hydroxide ions (OH⁻) in water. Their common properties include:

• Taste bitter and feel slippery (like soap).

• Turn red litmus paper blue.

• Neutralize acids.

Examples of common bases include:

• Sodium hydroxide (NaOH), used in soap-making.

• Magnesium hydroxide (Mg(OH)₂), found in antacids to soothe indigestion.

🔹 What are Salts?

Salts are formed when acids react with bases. In this reaction, water and salt are produced. This process is called neutralization. Salts have many uses in cooking, industry, and agriculture.

Example:

Acid+Base→Salt+Water

Hydrochloric acid(HCl)+Sodium hydroxide(NaOH)→Sodium chloride(NaCl)+Water(H2O) 

🧪 Real-Life Example

🔹 Neutralizing Stomach Acid: Have you ever had heartburn or indigestion after eating spicy food? This happens when there is too much hydrochloric acid in your stomach. To relieve the pain, people often take antacids. Antacids contain bases like magnesium hydroxide (Mg(OH)₂) that neutralize the excess acid, forming salts and water, relieving the discomfort.

🧩 Sample Problem Walkthrough

🧠 Problem:
A student accidentally spills hydrochloric acid on the laboratory bench. Suggest a suitable chemical to neutralize this acid spill and explain your choice.

✅ Step-by-Step Solution:

• Step 1: Identify the spilled substance (acid: HCl).

• Step 2: Recall acids are neutralized by bases.

• Step 3: Select a common base (e.g., Sodium bicarbonate — baking soda, NaHCO₃).

• Step 4: Write the neutralization equation:

                  HCl+NaHCO3→NaCl+CO2+H2O

• Step 5: Confirm harmless products (salt, water, and carbon dioxide).

✔️ Answer:
Use baking soda (NaHCO₃) because it safely neutralizes the acid, producing harmless salt (NaCl), water, and carbon dioxide (CO₂).

✍🏽 Practice Exercises

1. Fill in the blanks:

(a) Acids produce ______ ions in water.
(b) Bases taste ______ and feel ______.

Answers:
(a) Hydrogen (H⁺)
(b) Bitter, slippery

2. Match the substances to their type:

Answers:

• Lemon Juice → Acid

• Soap → Base

• Table Salt → Salt

3. Short Answer:

Explain why farmers might test the soil on their farms using acids and bases knowledge.

Sample Answer:
Farmers test soil acidity (pH) because certain crops grow best at specific pH levels. Knowing if the soil is acidic or basic helps them decide how much fertilizer or lime is needed for healthy plant growth.

🌀 Recap

Today, we learned:

• Acids release H⁺ ions, taste sour, and turn blue litmus red.

• Bases release OH⁻ ions, taste bitter, feel slippery, and turn red litmus blue.

• Salts result from neutralizing acids and bases.

• Real-world applications include antacids to relieve indigestion and neutralizing chemical spills.

💭 Reflection Prompt

Think about something acidic or basic you’ve used or encountered today—maybe vinegar, toothpaste, or soap. Write down in your notebook why you think it’s acidic or basic and how knowing this helps you in daily life. Discuss your answers with a friend or family member.