Science
Experiment: Titration of Acidic Household Substances
Objective
The purpose of this experiment is to determine the molarity and weight/volume percent of acetic acid in vinegar by titration with sodium hydroxide to a phenolphthalein endpoint. This procedure may be modified by titrating an acidic beverage such 7-up or Sprite.
Equipment and Material (Total Time 60 – 90 min.)
Variety of Berel Pipet
Long glass stirring rod
Wash bottle
10-mL graduated cylinder
100 mL beakers
Material
NaOH, Sodium hydroxide Titrant solution
White vinegar phenolphthalein Distilled water Discussion
Acetic acid (CH3COOH) is the chemical compound which gives vinegar its pungent odor and sour taste. It contains one ionizable hydrogen atom, CH3COOH, (shown in bold type) In aqueous solution, when acetic acid reacts with a strong base like sodium hydroxide (NaOH), the hydroxide ion from the base reacts with the hydrogen ion from the acid to produce water. The remaining sodium ion (Na+) and the polyatomic (CH3COO-) acetate ion form the soluble salt sodium acetate, NaCH3COO(aq), which remains dissociated in solution. This acid-base reaction is called a neutralization reaction and has the general form:
Acid + base a salt + water
For the reaction of acetic acid with sodium hydroxide, the chemical equation is written as:
HC2H3O2(aq) + NaOH(aq) -(H2O) Na+(aq) + C2H3O2-(aq) + H2O(l)
The progress of a neutralization reaction can be monitored by using a pH indicator, such as phenolphthalein (see Experiment 11). This type of monitoring is called titration and involves the incremental addition of small amounts of base to the acid in the presence of a pH indicator. An indicator is chosen which will change color at a pH very close to the equivalence point of the titration. The equivalence point is defined as the point at which the number of moles of base added is equal to the number of moles of acid present in the solution being titrated. When the
Objective
The purpose of this experiment is to determine the molarity and weight/volume percent of acetic acid in vinegar by titration with sodium hydroxide to a phenolphthalein endpoint. This procedure may be modified by titrating an acidic beverage such 7-up or Sprite.
Equipment and Material (Total Time 60 – 90 min.)
Variety of Berel Pipet
Long glass stirring rod
Wash bottle
10-mL graduated cylinder
100 mL beakers
Material
NaOH, Sodium hydroxide Titrant solution
White vinegar phenolphthalein Distilled water Discussion
Acetic acid (CH3COOH) is the chemical compound which gives vinegar its pungent odor and sour taste. It contains one ionizable hydrogen atom, CH3COOH, (shown in bold type) In aqueous solution, when acetic acid reacts with a strong base like sodium hydroxide (NaOH), the hydroxide ion from the base reacts with the hydrogen ion from the acid to produce water. The remaining sodium ion (Na+) and the polyatomic (CH3COO-) acetate ion form the soluble salt sodium acetate, NaCH3COO(aq), which remains dissociated in solution. This acid-base reaction is called a neutralization reaction and has the general form:
Acid + base a salt + water
For the reaction of acetic acid with sodium hydroxide, the chemical equation is written as:
HC2H3O2(aq) + NaOH(aq) -(H2O) Na+(aq) + C2H3O2-(aq) + H2O(l)
The progress of a neutralization reaction can be monitored by using a pH indicator, such as phenolphthalein (see Experiment 11). This type of monitoring is called titration and involves the incremental addition of small amounts of base to the acid in the presence of a pH indicator. An indicator is chosen which will change color at a pH very close to the equivalence point of the titration. The equivalence point is defined as the point at which the number of moles of base added is equal to the number of moles of acid present in the solution being titrated. When the