CHM096 Article 6 Electrochemistry Essay

 CHM 096TUTORIAL 6 Mar 2013


1 . Decide the oxidation process number of the first term element in the next ions. a)Cr2O72 d)AsO33



2 . Identify whether all the reactants demonstrated in the subsequent half-reactions is being oxidized or reduced.

a)As4+  As3+

b)Cl2O7  HClO4

c)C2H4O  C2H6O

d)SO2  SO42−

e)Cr2O72−  Cr3+

3. Suggest whether each of the following is definitely or is not a redox reaction.

a)CaCl2 + 2NaF  CaF2 + NaCl

b)CaI2 & Cl2  CaCl2 + I2

c)PbO2 + 4HCl  PbCl2 + Cl2 + 2H2O

d)FeS & 2H+  Fe2+ + H2S

4. State whether SO2 acts as a great oxidising agent or like a reducing agent in each of the following redox reactions.

a)SO2 + Mg  2MgO + S i9000

b)3SO2 + Cr2O72− & 2H+  3SO42− + 2Cr3+ + H2O

c)SO2 + 2NO3−  SO42− + 2NO2

d)SO2 + 2H2S  3S + 2H2O

5. Write the well balanced ionic half-equation to show:

a)the oxidation of iodine (I2), in acid medium, to offer iodate ion (IO3−)

b)the reduction of vanadyl ion (VO2+) to provide vanadium (III) ion, in acid channel.

c) the reduction of manganese dioxide, in acid solution solution, to give manganese (II) ion.

6th. When birdwatcher metal is put in concentrated nitric acid solution, the solution turns green and brown girl NO2 gas evolved.

Cu(s) + 4HNO3(aq)  Cu(NO3)2(aq) + 2NO2(g) + 2H2O(l) a) Which will element is reduced?

b) Which factor is oxidised?

c) Which is the oxidising agent?

d) Which is the reducing agent?

7. When metallic zinc is included in an aqueous solution of silver nitrate, zinc dissolves and metallic is transferred.

a) Write a well-balanced molecular formula for the reaction.

b) Write the ionic half-equations for the oxidation and reduction reactions.

8. Make use of the redox half-reaction method to set a balanced net ionic formula for each in the following reactions occurring in acidic alternatives. a)Sn2+ & CrO4−  Sn4+ & Cr3+

b)AsO33 + IO3  AsO43 + I

c)Cr2O72 & Br2  Cr3+ + BrO3

d)NO3 + Cu  NO2 + Cu2+

e)S2O32 & OCl  S4O62 + Cl

f)PbO2 & Mn2+  Pb2+ + MnO4−

g)MnO4 + Bi3+  Mn2+ + BiO3

9. The response between BiO3−(aq) and Fe2+(aq) in acidulent medium has by the equation:

BiO3 + 2Fe2+ & 6H+  Bi3+ + 2Fe3+ & 3H2O

What volume of 0. 4 Meters BiO3 answer would be needed to react totally with 40 cm3 of 0. 2 M Fe2+ solution? (7. 5 cm3)

10. A redox titration is carried out between dichromate ion and chloride ion in acidulent solution. The response is given by equation:

Cr2O72 + Cl− + H+  Cr3+ + Cl2 + WATER (unbalanced) a) Write the balanced ionic formula for the response.

b) If 20. your five cm3 of 0. 5 M chloride solution reacts completely with 6. almost 8 cm3 associated with an acidified dichromate solution, determine the molarity of the dichromate solution. (0. 3 M)

11. Write down thier IUPAC mention for the voltaic cell (galvanic cell) which has the overall cell response:

a)2Ag+(aq) + Cu(s)  2Ag(s) + Cu2+(aq)

b)2Fe3+(aq) + Mg(s)  2Fe2+(aq) + Mg2+(aq)

12. Solution the following questions using info from the Electrochemical Series.

a)Is H+(aq) capable of oxidising Cu(s) to Cu2+(aq)?

b)Is Fe(s) capable of minimizing Cu2+(aq) to Cu+(aq)?

c)Is Cl2(g) competent of oxidising Br−(aq) to Br2(l)?

13. In an research, a galvanic cell is placed to gauge the standard electrode potential (Eo) for the electrode Ni2+(aq) / Ni(s), using the regular hydrogen electrode (S. They would. E. ) as guide electrode, and saturated remedy of KCl as the electrolyte in the salt-bridge. The cell potential (Eocell) can be 0. twenty-five volt and Ni(s) has been oxidised.

a)State the standard circumstances applied to the 2 half-cells. b)Draw a fully marked diagram in the cell, suggesting the pluspol, the cathode and the path of electron flow. c)What is the Eo value pertaining to the...