Determination of the Dissociation Constant of Weak Acids .docx

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Names: Rithvik Chekuri, Helen Hsu, Mehar Johal, Kashif Ansari, Aakash MaheshWhite Group Block 3Determination of the Dissociation Constant of Weak Acids Lab ReportPurpose:To determine the dissociation constant of an unknown weak acid.Procedure:Make an acid solution using the unknown weak acid salt and neutralize half of theacid using sodium hydroxide. React the weak acid with the neutralized solution and determinethe pH of the final solution.Prelab:1.H3PO4+ H2OH2PO4-+ H3O+2.Ka=[[H2PO4-][H3O+]] / [H3PO4]3.-log(7.5x10-3) = pH 2.14.Phenolphthalein would not be an appropriate indicator because from a pH of one throughseven, the phenolphthalein indicator stays colorless. Orange IV would be a suitableindicator because it changes color when the pH is from two to three.5.H2PO4-H++ HPO42-Ka= [[H+][HPO42-]] / [H2PO4-]-log(6.2x10-8) = pH 7.26.HPO42-PO43-+ H+Ka3= [[H+][PO43-]] / [HPO42-]Ka3= [H+]-log(4.2x10-13) = pH 12.4MSDSSodium Hydroxide (NaOH)-Stable in normal conditions. Avoid water, combustible materials, and acids.-Will cause corrosion, burning, and possible permanent damage in contact with the body.-Wear goggles, apron and gloves and follow safety procedures.Baking Soda (NaHCO3)-Stable in normal conditions. Avoid oxidizing agents and strong acids.- In cases of skin contact it will cause irritation. May cause respiratory irritation.-Wear goggles, apron and gloves and follow safety procedures.
Phenolphthalein (C20H14O4)-Stable in normal conditions.Avoid oxidizing agents, strong acids, and bases.-Can cause eye irritation, drowsiness, dizziness, or cancer.-Wear goggles, apron and gloves and follow safety procedures.Acetic Acid (HC2H3O2)-Stable in normal conditions. Avoid strong oxidizing agents.-Can cause serious eye damage and skin corrosion. It is also toxic if inhaled.-Wear goggles, apron and gloves and follow safety procedures.Benzoic Acid (C7H6O2)-Stable in normal conditions. Avoid strong oxidizing agents, strong reducing agents, and strongbases.- Can cause severe eye irritation and skin irritation.-Wear goggles, apron and gloves and follow safety procedures.Potassium Dihydrogen Phthalate (KH2PO4)-Stable in normal conditions.-May cause skin and respiratory irritation.-Wear goggles, apron and gloves and follow safety procedures.Potassium Hydrogen Phthalate (C8H5KO4)-Stable in normal conditions. Avoid strong oxidizing agents, strong reducing agents,strongbases, and Nitric Acid.-May cause skin and respiratory irritation.-Wear goggles, apron and gloves and follow safety procedures.Sodium Dihydrogen Phosphate (NaH2PO4)-Stable in normal conditions. Avoid strong acids.-May cause serious eye damage, skin corrosion, and irritation.-Wear goggles, apron and gloves and follow safety procedures.

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Term
Fall
Professor
gg
Tags
pH, eye irritation

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