Chapter 25, Problem 56P

Name Section Score Date EXERCISE B pH, pOH, pка, AND PKD CALCULATIONS 1. Complete the following table. Solution [H+] [OH-] PH РОН Nature of Solution A 2 x 10-8 M B 1 x 10-7 M C D 12.3 6.8 2. The following table contains the names, formulas, ka or pka for some common acids. Fill in the blanks in the table. (17 Points) Acid Name Formula Dissociation reaction Ka pka Phosphoric acid H₂PO₁ H3PO4 H++ H₂PO 7.08 x 10-3 Dihydrogen H₂PO H₂PO H+ HPO 6.31 x 10-6 phosphate Hydrogen HPO₁ 12.4 phosphate Carbonic acid H2CO3 Hydrogen HCO 6.35 10.3 carbonate or bicarbonate Acetic acid CH,COOH 4.76 Lactic acid CH₂CHOH- COOH 1.38 x 10 Ammonium NH 5.63 x 10-10 Phenol CH₂OH 1 x 10-10 Protonated form CH3NH3* 3.16 x 10-11 of methylamine

Indicate whether it is true that Co(III) complexes are very stable.

MnO2 acts as an oxidant in the chlorine synthesis reaction.

In Potassium mu-dihydroxydicobaltate (III) tetraoxalate K4[Co2(C2O4)4(OH)2], indicate whether the OH ligand type is bidentate.

Imagine an electrochemical cell based on these two half reactions with electrolyte concentrations as given below:   Oxidation: Pb(s) → Pb2+(aq, 0.10 M) + 2 e– Reduction: MnO4–(aq, 1.50 M) + 4 H+(aq, 2.0 M) + 3 e– → MnO2(s) + 2 H2O(l) Calculate Ecell (assuming temperature is standard 25 °C).

: ☐ + Draw the Fischer projection of the most common naturally-occurring form of aspartate, with the acid group at the top and the side chain at the bottom. Important: be sure your structure shows the molecule as it would exist at physiological pH. Click and drag to start drawing a structure. ✓

For a silver-silver chloride electrode, the following potentials are observed: E°cell = 0.222 V and E(saturated KCl) = 0.197 V Use this information to find the [Cl–] (technically it’s the activity of Cl– that’s relevant here, but we’ll just call it “concentration” for simplicity) in saturated KCl.

A concentration cell consists of two Sn/Sn2+ half-cells. The cell has a potential of 0.10 V at 25 °C. What is the ratio of [Sn2+] (i.e., [Sn2+left-half] / [Sn2+right-half])?

Electrochemical cell potentials can be used to determine equilibrium constants that would be otherwise difficult to determine because concentrations are small. What is Κ for the following balanced reaction if E˚ = +0.0218 V?   3 Zn(s) + 2 Cr3+(aq) → 3 Zn2+(aq) + Cr(s)           E˚ = +0.0218 V