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SENIOR HIGH SCHOOL REPORTChem Lab - Lab Report. Redox equations. Im sure everyone that has done anytype of chemistry at any time in there lives have done this experiment. Anyway if u want the original just msg me where u want it sent.
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Mark Riley 3107631608 Investigating Redox Reactions 1
Investigating Redox Reactions
Mark Riley
Introduction Redox reactions are oxidation-reduction reactions which are complementary chemical reactions characterised by the loss or gain, respectively, of one or more electrons by a substance.
Task Practical Report
Aim To determine the redox reaction that has taken place after mixing some common oxidants and reactants.
Procedure This experiment has been split into 7 parts. A separate procedure for each test is given.
Also- See page 6 of the Practical Activities handbook
Equipment Safety glasses, test tube rack, 7 test tubes, reagents in dropping bottle
Mark Riley 3107631608 Investigating Redox Reactions 2
The πΈ0 given for each half and overall equations have been highlighted as they are only hypothetical values
(eg. if one mole of each was used, at 25oc, oxidation and reduction separated etc in a voltaic battery)
1. Reaction of acidified hydrogen peroxide with iron sulphate
5 drops of π»2π2, 5 drops of π»2ππ4 and 10 drops of πΉπππ4 were added to a test tube. 1 drop of
KSCN was added and as a result the solution turned blood red indicating the presence of πΉπ3+.
π»2π2 has a higher oxidising strength (oxidant) and πΉπ2+ has a higher reducing strength
(reductant) β΄ the πΉπ2+ was oxidized and π»2π2 was reduced according to the following equation.
πΉπ2+ β πΉπ3+ + π Γ 2 β 0.77V
π»2π2 + 2π»+ + 2π β 2π»2π + 1.78V
π»2π2 + 2π»+ + 2πΉπ2+ β 2π»2π + 2πΉπ3+ βV = 1.01V
2. Reaction of acidified hydrogen peroxide with potassium iodide
5 drops of π»2π2, 5 drops of π»2ππ4 and 10 drops of πΎπΌ(white crystalline solid, colourless in
solution) were added to a test tube. 3 drops of starch were added turning the solution blue-black
indicating the presence of iodine πΌ2.
π»2π2 has a higher oxidising strength (oxidant) and πΌβ has a higher reducing strength (reductant) β΄
the πΌβ was oxidized and π»2π2 was reduced according to the following equation.
2πΌβ β πΌ2 + 2π β 0.54V
π»2π2 + 2π»+ + 2π β 2π»2π + 1.78V
π»2π2 + 2π»+ + 2πΌβ β 2π»2π + πΌ2 βV = 1.24V
Mark Riley 3107631608 Investigating Redox Reactions 3
3. Reaction of acidified potassium permanganate with iron(II)sulphate
3 drops of πΎπππ4, 6 drops of π»2ππ4 and 20 drops of πΉπππ4 were added to a test tube. The
solution was initially purple but then turned colourless indicating that the πππ4β had been
reduced to ππ2+. 1 drop of KSCN was added and as a result the solution turned blood red
indicating the presence of πΉπ3+.
πππ4β has a higher oxidising strength (oxidant) and πΉπ2+ has a higher reducing strength
(reductant) β΄ the πΉπ2+ is oxidized and πππ4β is reduced according to the following equation.
πΉπ2+ β πΉπ3+ + π Γ 5 β 0.77V
πππ4β + 8π»+ + 5π β ππ2+ + 4π»2π + 1.51V
πππ4β + 8π»+ + 5πΉπ2+ β ππ2+ + 4π»2π + 5πΉπ3+ βV = 0.74
4. Reaction of acidified potassium permanganate with potassium iodide
3 drops of πΎπππ4, 6 drops of π»2ππ4 and 20 drops of πΎπΌ(white crystalline solid, colourless in
solution) were added to a test tube. The solution was initially purple but then turned colourless
indicating that the πππ4β had been reduced to ππ2+. 3 drops of starch were added turning the
solution blue-black indicating the presence of iodine πΌ2. A precipitate was also present.
πππ4β has a higher oxidising strength (oxidant) and 2πΌβ has a higher reducing strength (reductant)
β΄ the 2πΌβ is oxidized and πππ4β is reduced according to the following equation.
2πΌβ β πΌ2 + 2π Γ 5 β 0.54V
πππ4β + 8π»+ + 5π β ππ2+ + 4π»2π Γ 2 + 1.51V
2πππ4β + 2 Γ 8π»+ + 5 Γ 2πΌβ β 2ππ2+ + 2 Γ 4π»2π + 5πΌ2
2πππ4β + 16π»+ + 10πΌβ β 2ππ2+ + 8π»2π + 5πΌ2 βV = 0.97
Mark Riley 3107631608 Investigating Redox Reactions 4
5. Reaction of acidified potassium dichromate with potassium iodide
2 drops of πΎ2πΆπ2π7, 6 drops of π»2ππ4 and 15 drops of πΎπΌ (white crystalline solid, colourless in
solution) were added to a test tube. The orange solution turned blue/green indicating that the
πΆπ2π72β had been reduced to πΆπ3+. 3 drops of starch were added turning the solution blue-black
indicating the presence of iodine πΌ2.
πΆπ2π72β has a higher oxidising strength (oxidant) and 2πΌβ has a higher reducing strength
(reductant) β΄ the 2πΌβ is oxidized and πΆπ2π72β is reduced according to the following equation.
2πΌβ β πΌ2 + 2π Γ 3 β 0.54V
πΆπ2π72β + 14π»+ + 6π β 2πΆπ3+ + 7π»2π + 1.23V
πΆπ2π72β + 14π»+ + 6πΌβ β 2πΆπ3+ + 7π»2π + 3πΌ2 βV = 0.69V
6. Reaction of iron(III)chloride with acidified hydrogen peroxide
5 drops of πΉππΆπ3 , 5 drops of π»2ππ4 and 5 drops of π»2π2 were added to a test tube. 1 drop of
KSCN was added, the colour of the solution was unchanged indicating that no πΉπ3+ was present.
The solution fizzled indicating a the release of oxygen gas π2.
πΉπ3+ has a higher oxidising strength (oxidant) and π»2π2 has a higher reducing strength
(reductant) β΄ the π»2π2 is oxidized and πΉπ3+ is reduced according to the following equation.
πΉπ3+ + π β πΉπ2+ Γ 2 + 0.77V
π»2π2 β π2 + 2π»+ + 2π β 0.70V
π»2π2 + 2πΉπ3+ β π2 + 2π»+ + 2πΉπ2+ βV = 0.07V
Mark Riley 3107631608 Investigating Redox Reactions 5
7. Reaction of acidified potassium permanganate with hydrogen peroxide
3 drops of πΎπππ4, 6 drops of H2ππ4 and 10 drops of π»2π2 were added to a test tube. The
solution fizzled indicating the release of oxygen gas π2.
πππ4β has a higher oxidising strength (oxidant) and π»2π2 has a higher reducing strength
(reductant) β΄ the π»2π2 is oxidized and πππ4βis reduced according to the following equation.
π»2π2 β π2 + 2π»+ + 2π Γ 5 β 0.70V
πππ4β + 8π»+ + 5π β ππ2+ + 4π»2π Γ 2 + 1.51V
2πππ4β + 2 Γ 8π»+ + 5π»2π2 β 2ππ2+ + 2 Γ 4π»2π + 5π2 + 5 Γ 2π»+
2πππ4β + 16π»+ + 5π»2π2 β 2ππ2+ + 8π»2π + 5π2 + 10π»+
2πππ4β + 6π»+ + 5π»2π2 β 2ππ2+ + 8π»2π + 5π2 βV = 0.81
Conclusion
Redox reactions were balanced in the form of chemical equations by arranging the quantities of
the substances involved so that the number of electrons lost by one substance is equaled by the
number gained by another substance. In redox reactions, the substance losing electrons
(undergoing oxidation) is a good electron donor, or reductant because lost electrons are given to
and reduce the other substance. The other substance that gained electrons (undergoing
reduction) is an electron acceptor, or oxidant. Hydrogen peroxide was capable of acting as a
reductant as well as an oxidant.