Method 1: Titration with Potassium Permanganate
5 H2O2 + 2 MnO4- + 6 H+ --> 8 H2O + 5 O2 + 2 Mn2+
Method 2: Catalytic Decomposition to Water and Oxygen
2 H2O2 --> 2 H2O + O2
Method 3: Oxidation of Iodide to Iodine; Spectroscopic measurement of TriIodide ion.
IO3- + 5 I- + 6 H+ --> 3 H2O + 3 I2 (standard)
H2O2 + 2 I- + 2 H+ --> 2 H2O + I2 (unknown)
I- + I2 --> I3-
Method 1:
You weigh out Potassium Permanganate,
Mass of KMnO4 (MW=158.034).......... 0.1736 g
You dissolve it completely in water.......... 46.00 mL
(a) Molarity of MnO4- solution........................... ________________ M
You pipet out your UNKNOWN............. 0.90 mL
You acidify and titrate it with your KMnO4 solution until the permanganate color persists.
Volume of permanganate solution.......... 11.39 mL
(b) Molarity of the HOOH in the UNKNOWN...................................._____________ M
Method 2:
You pipet your UNKNOWN into a reaction tube.... 4.40 mL
Add a "boat" containing Manganese Dioxide, MnO2
Set up the gas collection apparatus shown on the right.
You sink the boat and allow the oxygen generated to collect in the collection flask. The water temperature is................. 27 oC
The Barometric Pressure is............... 761.9 mm Hg
Weight of the collection Flask with remaining water.... 154.81 g.
Weight of collection flask filled with water........... 200.70 g.
DensityH2O ................................. 0.996 g/cc
(c) Partial Pressure of Oxygen collected................................. ____________ mm Hg
(d) Volume of oxygen collected ...................................... ____________ mL
(e) Millimoles of oxygen gas generated.................................. ____________ mmol
(f) Molarity of Hydrogen Peroxide in UNKNOWN.......................... ____________ M
Method 3:
STANDARD: Put into a clean 250 mL volumetric flask exactly ..... 1.00 ml
of 0.95 mM iodate STANDARD.
Add an excess of 1M KI and 1M Sulfuric Acid and let stand for 5 minutes. Dilute to volume.
UNKNOWN: Pipet into a clean 250 mL volumetric flask 1.00 mL of your UNKNOWN and dilute to volume with distilled water.
Put into a clean 250 mL volumetric flask exactly ........ 1.00 mL
of this diluted H2O2 UNKNOWN.Add an excess of 1M KI and 1M Sulfuric Acid and let stand for 5 minutes. Dilute to volume (250 mL). Measure STANDARD and UNKNOWN spectroscopically at 360 nm using the same cuvet throughout.
% Transmission of BLANK.................................. 98.1 %
% Transmission of STANDARD................................ 48.5 %
% Transmission of UNKNOWN................................. 34.7 %
(g) Absorbance of STANDARD.................................... ___________________
(h) Absorbance of UNKNOWN.................................... ___________________
(i) Molarity of original UNKNOWN................................. ___________________ M
Method 1: Titration with Potassium Permanganate
5 H2O2 + 2 MnO4- + 6 H+ --> 8 H2O + 5 O2 + 2 Mn2+
Method 2: Catalytic Decomposition to Water and Oxygen
2 H2O2 --> 2 H2O + O2
Method 3: Oxidation of Iodide to Iodine; Spectroscopic measurement of TriIodide ion.
IO3- + 5 I- + 6 H+ --> 3 H2O + 3 I2 (standard)
H2O2 + 2 I- + 2 H+ --> 2 H2O + I2 (unknown)
I- + I2 --> I3-
Method 1:
You weigh out Potassium Permanganate,
Mass of KMnO4 (MW=158.034).......... 0.1736 g
You dissolve it completely in water.......... 46.00 mL
(a) Molarity of MnO4- solution........................... ________________ M
You pipet out your UNKNOWN............. 0.90 mL
You acidify and titrate it with your KMnO4 solution until the permanganate color persists.
Volume of permanganate solution.......... 11.39 mL
(b) Molarity of the HOOH in the UNKNOWN...................................._____________ M
Method 2:
You pipet your UNKNOWN into a reaction tube.... 4.40 mL
Add a "boat" containing Manganese Dioxide, MnO2
Set up the gas collection apparatus shown on the right.
You sink the boat and allow the oxygen generated to collect in the collection flask. The water temperature is................. 27 oC
The Barometric Pressure is............... 761.9 mm Hg
Weight of the collection Flask with remaining water.... 154.81 g.
Weight of collection flask filled with water........... 200.70 g.
DensityH2O ................................. 0.996 g/cc
(c) Partial Pressure of Oxygen collected................................. ____________ mm Hg
(d) Volume of oxygen collected ...................................... ____________ mL
(e) Millimoles of oxygen gas generated.................................. ____________ mmol
(f) Molarity of Hydrogen Peroxide in UNKNOWN.......................... ____________ M
Method 3:
STANDARD: Put into a clean 250 mL volumetric flask exactly ..... 1.00 ml
of 0.95 mM iodate STANDARD.
Add an excess of 1M KI and 1M Sulfuric Acid and let stand for 5 minutes. Dilute to volume.
UNKNOWN: Pipet into a clean 250 mL volumetric flask 1.00 mL of your UNKNOWN and dilute to volume with distilled water.
Put into a clean 250 mL volumetric flask exactly ........ 1.00 mL
of this diluted H2O2 UNKNOWN.Add an excess of 1M KI and 1M Sulfuric Acid and let stand for 5 minutes. Dilute to volume (250 mL). Measure STANDARD and UNKNOWN spectroscopically at 360 nm using the same cuvet throughout.
% Transmission of BLANK.................................. 98.1 %
% Transmission of STANDARD................................ 48.5 %
% Transmission of UNKNOWN................................. 34.7 %
(g) Absorbance of STANDARD.................................... ___________________
(h) Absorbance of UNKNOWN.................................... ___________________
(i) Molarity of original UNKNOWN................................. ___________________ M
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