Exp. 5 Buffer solution

• Buffer solution is a solution that can maintain its acidity or basicity when a small amount of acid or base is added.
• The pH of the solution remains unchanged or changes only slightly.
• A buffer solution composed of a weak acid and its salt, such as CH3COOH and CH3COONa, has a pH value less than 7
• A buffer solution composed of a weak base and its salt, such as NH4OH and NH4Cl, will have a pH value greater than 7.
• The concentration of CH3COOH comes from the prepared acetic acid, while the acetate ion CH3COOis considered to only come from the salt CH3COONa because the salt CH3COONa completely 100% dissociates and is present in large quantities.
• pH calculation

  A) pKa

  B) -

  C) log

  D) Acid

  E) salt

  
• The buffer system of CH3COOH and CH3COONa, when acid or base is added, maintains an acidic-base equilibrium or prevents significant changes in the pH of the solution
• The buffer capacity of a buffer solution refers to its ability to undergo reactions with added acid or base in a way that causes the pH to change by less than 1 pH unit per 1 dm3 of the buffer solution
• the buffer capacity is calculated based on the amount of acid or base per liter and the resulting change in pH per unit.
• THe buffer solution of NH3 and NH4Cl cal expressed as

  A) pOH

  B) pKb

  C) -

  D) log

  E) Base

  F) salt

  
• Reaction

  A) CH3COO-

  B) +

  C) H3O+

  D) CH3COOH

  E) +

  F) H2O

  G) CH3COOH

  H) +

  I) OH-

  J) CH3COO-

  K) +

  L) H2O

  
• Buffer solution is primarily used for maintaining a stable pH
• pH range is typically depends on the specific buffer components and the pH of the buffer.