What Do All Acids And All Bases Have In Common?

Introduction

Although acids and bases are chemically opposite in nature, all acids share certain properties, and all bases share certain characteristics due to the ions they release in aqueous solutions. Understanding the common properties of acids and bases helps us recognize how these substances behave in various chemical reactions and everyday applications.

Common Properties of Acids

All acids, when dissolved in water, exhibit certain common properties due to the release of hydrogen ions ().

Release of Hydrogen Ions () in Water

• The defining characteristic of an acid is that it produces hydrogen ions () when dissolved in water.
  • Example:
    Hydrochloric acid () dissociates in water to release ions:
    
  • Sulfuric acid () dissociates to release two hydrogen ions:
    
• ions make acids behave the way they do, contributing to their sour taste, their ability to conduct electricity, and their reactivity with metals and carbonates.

Acids Change the Color of Indicators

• Acids affect indicators like litmus paper, phenolphthalein, and methyl orange in predictable ways:
  • Acids turn blue litmus paper red.
  • Phenolphthalein remains colorless in acids.
  • Methyl orange turns red in acidic solutions
• These changes occur because the ions interact with the chemical structure of the indicators, causing them to change color..

Acids Conduct Electricity

• All acids conduct electricity in aqueous solutions due to the presence of free-moving ions ( and the respective anions).
  • Example:
    Hydrochloric acid () conducts electricity because it dissociates into and ions in water.

Acids React with Metals

• Acids react with active metals (like zinc, magnesium, iron) to release hydrogen gas ().
  • Example:
    
• Common Behavior: All acids release hydrogen gas when they react with metals, and this gas burns with a ‘pop’ sound.

Acids Neutralize Bases

• Acids can neutralize bases (alkalis) to form salt and water.
  • Example:
    
• This is known as a neutralization reaction, where the acidic and basic properties are canceled out.

Common Properties of Bases

All bases, when dissolved in water, share common properties because they release hydroxide ions ().

Release of Hydroxide Ions () in Water

• The defining property of a base is that it produces hydroxide ions () when dissolved in water.
• Example:
  • Sodium hydroxide () dissociates in water to release ions:
    
  • Potassium hydroxide () dissociates to release and ions:
    
• ions are responsible for the slippery feel, bitter taste, and alkaline nature of bases.

Bases Change the Color of Indicators

• Like acids, bases also change the color of indicators:
  • Bases turn red litmus paper blue.
  • Phenolphthalein turns pink in basic solutions.
  • Methyl orange turns yellow in basic solutions.
• These color changes occur due to the interaction of ions with the chemical structure of the indicators.

Bases Conduct Electricity

• Bases, when dissolved in water, dissociate into positive and negative ions ( and respective cations), allowing them to conduct electricity.
  • Example:
    Sodium hydroxide () solution conducts electricity due to the presence of and ions.

Bases React with Acids

• Bases react with acids in a neutralization reaction, producing salt and water.
  • Example:
    

• Common Behavior: All bases neutralize acids by combining with H⁺ ions to form water, reducing both the acidic and basic properties of the reactants.

Bases React with Certain Metals

• Some bases (like sodium hydroxide) react with amphoteric metals (e.g., zinc, aluminum) to release hydrogen gas.
  • Example:

Common Behavior of Acids and Bases in Water

Dissociation in Water:

• Both acids and bases dissociate in water to release ions:
  • Acids release ions.
  • Bases release ions.

• These ions make acids and bases conduct electricity and participate in various chemical reactions.

Conductivity in Water:

• Acids: Conduct electricity due to the movement of ions.
• Bases: Conduct electricity due to the movement of ions.

Electrolyte Behavior:

• Both acids and bases are electrolytes because they dissociate into ions in water, allowing them to carry an electric current. The strength of the electrolyte depends on the degree of dissociation.
  • Strong acids and bases (e.g., , ) dissociate completely, making them strong electrolytes.
  • Weak acids and bases (e.g., acetic acid, ammonium hydroxide) dissociate partially, making them weak electrolytes.

Real-life Applications of Acids and Bases

Applications of Acids:

• Acids in Digestion: Hydrochloric acid () in the stomach helps break down food during digestion.
• Acids in Industry: Sulfuric acid () is widely used in the manufacture of fertilizers, paints, and detergents.

Applications of Bases:

• Soaps and Detergents: Sodium hydroxide () is used in the production of soaps, detergents, and cleaners.
• Baking: Baking soda () reacts with acids to produce carbon dioxide, which helps baked goods rise.
• Medicinal Use: Magnesium hydroxide () is used as an antacid to neutralize excess stomach acid and relieve indigestion.

Practice Questions with Answers

Q1. What happens when hydrochloric acid is dissolved in water?

• Answer: When hydrochloric acid is dissolved in water, it dissociates to release hydrogen ions () and chloride ions ().
  • Equation :

Q2. Write the balanced chemical equation for the neutralization of sodium hydroxide with hydrochloric acid.

• Answer:  Sodium hydroxide neutralizes hydrochloric acid to form sodium chloride and water.
  • Equation :

Q3. How do you test if a substance is acidic or basic using litmus paper?

• Answer: If the substance turns blue litmus paper red, it is acidic.
                    If the substance turns red litmus paper blue, it is basic.

Q4. Why do acids conduct electricity in water?

• Answer: Acids conduct electricity in water because they dissociate to release hydrogen ions (H⁺), which are responsible for conducting electric current.

FAQs