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.