Acids and Alkalis

Acids and Alkalis

Definition and Properties

• Acids: Substances that donate a proton (H+ ion) in a solution, increasing the concentration of H+ ions.
  • Examples: Hydrochloric acid (HCl), Sulfuric acid (H2SO4), Nitric acid (HNO3)
  • Characteristics: Sour taste, corrosive, turn litmus paper red
• Alkalis: Substances that accept a proton (H+ ion) in a solution, decreasing the concentration of H+ ions.
  • Examples: Sodium hydroxide (NaOH), Calcium hydroxide (Ca(OH)2), Ammonia (NH3)
  • Characteristics: Bitter taste, feel slippery, turn litmus paper blue

pH Scale

• pH: A measure of the concentration of H+ ions in a solution
  • pH 7: Neutral (neither acidic nor alkaline)
  • pH < 7: Acidic
  • pH > 7: Alkaline
• pH Range:
  • Strong acids: pH 1-3 (e.g., HCl, H2SO4)
  • Weak acids: pH 4-6 (e.g., citric acid, vinegar)
  • Strong alkalis: pH 12-14 (e.g., NaOH, Ca(OH)2)
  • Weak alkalis: pH 8-11 (e.g., ammonia, baking soda)

Reactions

• Acid-Base Neutralization: The reaction between an acid and an alkali to form a salt and water
  • Example: HCl (acid) + NaOH (alkali) → NaCl (salt) + H2O (water)
• Acid-Metal Reaction: The reaction between an acid and a metal to form a salt and hydrogen gas
  • Example: HCl (acid) + Zn (metal) → ZnCl2 (salt) + H2 (gas)

Importance

• Biological Systems: Acids and alkalis play crucial roles in biological processes, such as digestion and metabolism
• Industrial Applications: Acids and alkalis are used in various industrial processes, including manufacturing, cleaning, and water treatment
• Environmental Impact: The imbalance of acid and alkali levels can affect the environment, leading to issues like acid rain and ocean acidification

Acids and Alkalis

• Acids are substances that donate a proton (H+ ion) in a solution, increasing the concentration of H+ ions.
• Examples of acids include Hydrochloric acid (HCl), Sulfuric acid (H2SO4), and Nitric acid (HNO3).
• Acids have a sour taste, are corrosive, and turn litmus paper red.

Alkalis

• Alkalis are substances that accept a proton (H+ ion) in a solution, decreasing the concentration of H+ ions.
• Examples of alkalis include Sodium hydroxide (NaOH), Calcium hydroxide (Ca(OH)2), and Ammonia (NH3).
• Alkalis have a bitter taste, feel slippery, and turn litmus paper blue.

pH Scale

• pH is a measure of the concentration of H+ ions in a solution.
• pH 7 is neutral (neither acidic nor alkaline).
• pH < 7 is acidic, and pH > 7 is alkaline.
• pH Range:
  • Strong acids: pH 1-3 (e.g., HCl, H2SO4).
  • Weak acids: pH 4-6 (e.g., citric acid, vinegar).
  • Strong alkalis: pH 12-14 (e.g., NaOH, Ca(OH)2).
  • Weak alkalis: pH 8-11 (e.g., ammonia, baking soda).

Reactions

• Acid-Base Neutralization: the reaction between an acid and an alkali to form a salt and water.
  • Example: HCl (acid) + NaOH (alkali) → NaCl (salt) + H2O (water).
• Acid-Metal Reaction: the reaction between an acid and a metal to form a salt and hydrogen gas.
  • Example: HCl (acid) + Zn (metal) → ZnCl2 (salt) + H2 (gas).

Importance

• Biological Systems: acids and alkalis play crucial roles in biological processes, such as digestion and metabolism.
• Industrial Applications: acids and alkalis are used in various industrial processes, including manufacturing, cleaning, and water treatment.
• Environmental Impact: the imbalance of acid and alkali levels can affect the environment, leading to issues like acid rain and ocean acidification.

Understand the definition and properties of acids and alkalis, including examples and characteristics of each.