Question 1

Determine the oxidation states of sulfur in the following compounds (i) H2S (ii) SO2 and (iii) H2SO3.

Accepted Answer

A)  (i) -2 (ii) +4 (iii) +6. 
B)  (i) +2 (ii) +4 (iii) + 6. 
C)  (i) -2 (ii) +4 (iii) +4. 
A)  (i) -2 (ii) +4 (iii) +6. 
B)  (i) +2 (ii) +4 (iii) + 6. 
C)  (i) -2 (ii) +4 (iii) +4. C

Question 2

Which of the following half-reactions should be affected by the change in H+ concentration:
(i) ClO2-(aq) + H2O(l) + 2e- → ClO-(aq) + 2OH-(aq)
(ii) MnO2(s) + 4H+(aq) +2e- → Mn2+(aq) + 2H2O(l)
(iii) ½ Cl2(aq) + e- → Cl-(aq)

Accepted Answer

A)  (i) and (iii) 
B)  (ii) and (iii) 
C)  (i) and (ii) 
A)  (i) and (iii) 
B)  (ii) and (iii) 
C)  (i) and (ii) C

Question 3

A redox reaction shifted to the right side when:

Accepted Answer

A) E0 = 0 B) E0 > 0 C) E0 < 0 A) E0 = 0 B) E0 > 0 C) E0 < 0 B

Question 4

According to Ellingham diagram, the reduction of Al2O3 with carbon is feasible above 2400F1F1F1S1F1F1F10C, why is Al2O3 reduced in practice electrochemically rather than chemically with carbon?

Accepted Answer

A)  The temperature is too high and maintaining it is too expensive. 
B)  It is difficult to achieve correct Al2O3-to-carbon ratio in practice. 
C)  Formed Al is reducing enough to reduce CO and CO2 back to carbon. 
A)  The temperature is too high and maintaining it is too expensive. 
B)  It is difficult to achieve correct Al2O3-to-carbon ratio in practice. 
C)  Formed Al is reducing enough to reduce CO and CO2 back to carbon.

Question 5

Find the correct statement about Latimer diagrams and one of their uses:

Accepted Answer

A)  In Latimer diagrams the oxidation numbers increase from left to right; a species can disproportionate into its two neighbours if the potential on the right is more negative than the potential on the left. 
B)  In Latimer diagrams the oxidation numbers decrease from left to right; a species can disproportionate into its two neighbours if the potential on the right is more negative than the potential on the left. 
C)  In Latimer diagrams the oxidation numbers decrease from left to right; a species can disproportionate into its two neighbours if the potential on the right is more positive than the potential on the left. 
A)  In Latimer diagrams the oxidation numbers increase from left to right; a species can disproportionate into its two neighbours if the potential on the right is more negative than the potential on the left. 
B)  In Latimer diagrams the oxidation numbers decrease from left to right; a species can disproportionate into its two neighbours if the potential on the right is more negative than the potential on the left. 
C)  In Latimer diagrams the oxidation numbers decrease from left to right; a species can disproportionate into its two neighbours if the potential on the right is more positive than the potential on the left.

Question 6

Which statement is correct in reference to the Frost diagrams?

Accepted Answer

A)  The maximum point on the diagram gives the most stable species with respect to the oxidation state zero which is set as a minimum point on the diagram. 
B)  The minimum point on the diagram represents the most stable species with respect to the oxidation state zero which is set at 0 on the diagram. 
C)  The maximum point on the diagram has the highest stability, and the lowest point, set at 0, corresponds to the least stable species. 
A)  The maximum point on the diagram gives the most stable species with respect to the oxidation state zero which is set as a minimum point on the diagram. 
B)  The minimum point on the diagram represents the most stable species with respect to the oxidation state zero which is set at 0 on the diagram. 
C)  The maximum point on the diagram has the highest stability, and the lowest point, set at 0, corresponds to the least stable species.

Question 7

Find the correct statement:

Accepted Answer

A)  Oxidizing agent oxidizes another species and is reduced during a redox reaction. 
B)  Half-reactions represent actual chemical processes 
C)  During a reduction process, a reducing agent releases electron(s). 
A)  Oxidizing agent oxidizes another species and is reduced during a redox reaction. 
B)  Half-reactions represent actual chemical processes 
C)  During a reduction process, a reducing agent releases electron(s).

Question 8

Find the correct statement(s) concerning the Pourbaix diagrams:
(i) A horizontal line separates species related by proton transfer only
(ii) A vertical line separates species related by electron transfer only
(iii) Sloped lines separate species related by both electron and proton transfer.

Accepted Answer

A)  All are correct 
B)  (i) and (ii) 
C)  Only (iii) 
A)  All are correct 
B)  (i) and (ii) 
C)  Only (iii)

Question 9

Which statement is the correct one?

Accepted Answer

A)  Comproportionation is a redox reaction in which the oxidation number of an element is simultaneously raised and lowered. Disproportionation is the opposite of comproportionation. 
B)  Disproportionation is a reaction in which the oxidation number of an element is raised. Comproportionation is a reaction in which the oxidation number of an element is lowered. 
C)  Disproportionation is a redox reaction in which the oxidation number of an element is simultaneously raised and lowered. Comproportionation is the opposite of disproportionation. 
A)  Comproportionation is a redox reaction in which the oxidation number of an element is simultaneously raised and lowered. Disproportionation is the opposite of comproportionation. 
B)  Disproportionation is a reaction in which the oxidation number of an element is raised. Comproportionation is a reaction in which the oxidation number of an element is lowered. 
C)  Disproportionation is a redox reaction in which the oxidation number of an element is simultaneously raised and lowered. Comproportionation is the opposite of disproportionation.

Question 10

In an Ox/Red couple:

Accepted Answer

A)  The more positive reduction potential is the more oxidizing Ox is. 
B)  The more positive reduction potential is the more reducing Red is. 
C)  The more negative reduction potential is the more oxidizing Ox is. 
A)  The more positive reduction potential is the more oxidizing Ox is. 
B)  The more positive reduction potential is the more reducing Red is. 
C)  The more negative reduction potential is the more oxidizing Ox is.

Determine the oxidation states of sulfur in the following compounds (i) H₂S (ii) SO₂ and (iii) H₂SO₃.

Which of the following half-reactions should be affected by the change in H⁺ concentration: (i) ClO₂^-(aq) + H₂O(l) + 2e^- → ClO^-(aq) + 2OH^-(aq) (ii) MnO₂(s) + 4H⁺(aq) +2e^- → Mn²⁺(aq) + 2H₂O(l) (iii) ½ Cl₂(aq) + e^- → Cl^-(aq)

A redox reaction shifted to the right side when:

According to Ellingham diagram, the reduction of Al₂O₃ with carbon is feasible above 2400C, why is Al₂O₃ reduced in practice electrochemically rather than chemically with carbon?

Find the correct statement about Latimer diagrams and one of their uses:

Which statement is correct in reference to the Frost diagrams?

Find the correct statement:

Find the correct statement(s) concerning the Pourbaix diagrams: (i) A horizontal line separates species related by proton transfer only (ii) A vertical line separates species related by electron transfer only (iii) Sloped lines separate species related by both electron and proton transfer.

Which statement is the correct one?

In an Ox/Red couple:

Atomic Structure

Molecular Structure and Bonding

Molecular Symmetry

The Structures of Simple Solids

Acids and Bases

An Introduction to Coordination Compounds

Physical Techniques in Inorganic Chemistry

Periodic Trends

Hydrogen

The Group 1 Elements

The Group 2 Elements

The Group 13 Elements

The Group 14 Elements

The Group 15 Elements

The Group 16 Elements

The Group 17 Elements

The Group 18 Elements

The D-Block Elements

The D-Metal Complexes: Electronic Structure and Spectra

Coordination Chemistry: Reactions of Complexes

D-Metal Organometallic Chemistry

The F-Block Metals

Materials Chemistry and Nanomaterials

Green Chemistry

Biological Inorganic Chemistry

Inorganic Chemistry in Medicine

Filters

Exam 6: Oxidation and Reduction

Determine the oxidation states of sulfur in the following compounds (i) H2S (ii) SO2 and (iii) H2SO3.

Which of the following half-reactions should be affected by the change in H+ concentration: (i) ClO2-(aq) + H2O(l) + 2e- → ClO-(aq) + 2OH-(aq) (ii) MnO2(s) + 4H+(aq) +2e- → Mn2+(aq) + 2H2O(l) (iii) ½ Cl2(aq) + e- → Cl-(aq)

A redox reaction shifted to the right side when:

According to Ellingham diagram, the reduction of Al2O3 with carbon is feasible above 2400C, why is Al2O3 reduced in practice electrochemically rather than chemically with carbon?

Find the correct statement about Latimer diagrams and one of their uses:

Which statement is correct in reference to the Frost diagrams?

Find the correct statement:

Find the correct statement(s) concerning the Pourbaix diagrams: (i) A horizontal line separates species related by proton transfer only (ii) A vertical line separates species related by electron transfer only (iii) Sloped lines separate species related by both electron and proton transfer.

Which statement is the correct one?

In an Ox/Red couple:

Atomic Structure

Molecular Structure and Bonding

Molecular Symmetry

The Structures of Simple Solids

Acids and Bases

An Introduction to Coordination Compounds

Physical Techniques in Inorganic Chemistry

Periodic Trends

Hydrogen

The Group 1 Elements

The Group 2 Elements

The Group 13 Elements

The Group 14 Elements

The Group 15 Elements

The Group 16 Elements

The Group 17 Elements

The Group 18 Elements

The D-Block Elements

The D-Metal Complexes: Electronic Structure and Spectra

Coordination Chemistry: Reactions of Complexes

D-Metal Organometallic Chemistry

The F-Block Metals

Materials Chemistry and Nanomaterials

Green Chemistry

Biological Inorganic Chemistry

Inorganic Chemistry in Medicine

Filters

Determine the oxidation states of sulfur in the following compounds (i) H₂S (ii) SO₂ and (iii) H₂SO₃.

Which of the following half-reactions should be affected by the change in H⁺ concentration: (i) ClO₂^-(aq) + H₂O(l) + 2e^- → ClO^-(aq) + 2OH^-(aq) (ii) MnO₂(s) + 4H⁺(aq) +2e^- → Mn²⁺(aq) + 2H₂O(l) (iii) ½ Cl₂(aq) + e^- → Cl^-(aq)

According to Ellingham diagram, the reduction of Al₂O₃ with carbon is feasible above 2400C, why is Al₂O₃ reduced in practice electrochemically rather than chemically with carbon?