Chemical Equation of Redox Reactions

[saikou]

Homework Statement

Please help me in chemical equations of redox reactions. Here are the problems.

1. Mixing potassium dichromate, K₂Cr₂O₇, and sulfuric acid, H₂SO₄, in a test tube. Then, add hydrogen peroxide, H₂O₂, drop by drop, shaking the solution after every drop. Add until a change occurs.

2. Putting iron (II) ammonium sulfate, Fe(NH₄)₂₍SO₄)₂, in a test tube. Add sulfuric acid, H₂SO₄, and potassium permanganate, KMnO₄. Shake the solution. Test the presence of iron (III) by adding a drop of potassium thiocyanate, KSCN. Iron (III) gives a dark red solution if present.

3. Put iron (III) chloride, FeCl₃, in a test tube and add potassium iodide, KI. Put a drop of potassium ferricyanide, K₃Fe(CN)₆. Iron (II) gives a dark blue precipitate if present.

4. Put iron (III) chloride, FeCl₃, in a test tube and potassium iodide, KI. Add hexane, C₆H₁₄. Iodine produces a pink carbon tetrachloride or hexane layer if present.

P.S. What is product of of oxidation and product of reduction?

Homework Equations

1. Potassium Dichromate = K₂Cr₂O₇
Sulfuric Acid = H₂SO₄
Hydrogen Peroxide = H₂O₂

2. Iron (II) Ammonium Sulfate = Fe(NH₄)₂₍SO₄)₂
Sulfuric Acid = H₂SO₄
Potassium Permanganate = KMnO₄
potassium Thiocyanate = KSCN
Iron (III) is present at the solution (I think)

3. Iron (III) Chloride = FeCl₃
Potassium Iodide = KI
Potassium Ferricyanide = K₃Fe(CN)₆
Iron (II) is present

4. Iron (III) Chloride = FeCl₃
Potassium Iodide = KI
Hexane = C₆H₁₄
Iodine is present

The Attempt at a Solution

I don't know what to include in the reaction so I'll leave it like this. :(

 

[Borek]

You have not put any information about observations in the first case, so I will leave it for now.

In third reaction you seem to be sure iron(II) was present. If so - it was not added into the mixture, so where did it come from?

 

[saikou]

UPDATED!

Homework Statement

Please help me in chemical equations of redox reactions. Here are the problems.

1. Mixing potassium dichromate, K₂Cr₂O₇, and sulfuric acid, H₂SO₄, in a test tube. Then, add hydrogen peroxide, H₂O₂, drop by drop, shaking the solution after every drop. Add until a change occurs.

2. Putting iron (II) ammonium sulfate, Fe(NH₄)₂₍SO₄)₂, in a test tube. Add sulfuric acid, H₂SO₄, and potassium permanganate, KMnO₄. Shake the solution. Test the presence of iron (III) by adding a drop of potassium thiocyanate, KSCN. Iron (III) gives a dark red solution if present.

3. Put iron (III) chloride, FeCl₃, in a test tube and add potassium iodide, KI. Put a drop of potassium ferricyanide, K₃Fe(CN)₆. Iron (II) gives a dark blue precipitate if present.

4. Put iron (III) chloride, FeCl₃, in a test tube and potassium iodide, KI. Add hexane, C₆H₁₄. Iodine produces a pink carbon tetrachloride or hexane layer if present.

P.S. What is product of of oxidation and product of reduction?

Homework Equations

1. Potassium Dichromate = K₂Cr₂O₇
Sulfuric Acid = H₂SO₄
Hydrogen Peroxide = H₂O₂
After mixing the potassium dichromate and sulfuric acid in a test tube, the color of the solution became light orange. The color of the chemical inside the test tube is changing bit by bit for every drop of hydrogen peroxide. First it’s greenish and after few drops, it became light blue.

2. Iron (II) Ammonium Sulfate = Fe(NH₄)₂₍SO₄)₂
Sulfuric Acid = H₂SO₄
Potassium Permanganate = KMnO₄
potassium Thiocyanate = KSCN
Iron (III) is present at the solution
Iron (II) ammonium sulfate, no color, is inside a test tube. After adding sulfuric acid and potassium permanganate in the test tube, the color turned into transparent dirty white. For testing the presence of iron (III): after adding a drop potassium thiocyanate, the color of the solution changed into red. Iron (III) gives a red solution if present.

3. Iron (III) Chloride = FeCl₃
Potassium Iodide = KI
Potassium Ferricyanide = K₃Fe(CN)₆
Iron (II) is present
Iron (III) chloride and potassium iodide are mixed in a test tube. The color of the solution changed from pale yellow into a bit darker one. After adding potassium ferricyanide, the solution turned dark blue. It means that iron (III) is present in the solution. Iron (III) gives a dark blue solution if present.

4. Iron (III) Chloride = FeCl₃
Potassium Iodide = KI
Hexane = C₆H₁₄
Iodine is present
Iron (III) chloride and potassium iodide are mixed in a test tube. The color of the solution changed from pale yellow into a bit darker one. For testing the presence of iodine: after adding hexane to the solution, the hexane layer turns pink which means iodine is present in the solution. Iodine is present when the color of the hexane layer turns pink.