In the table of standard reduction potentials, locate the half-reactions for the reductions of the following nonmetals: F 2 , Cl 2 , Br 2 , I 2 (reduction to halide ions), and O 2 , S, Se (reduction to H 2 X in aqueous acid). Among the elements, ions, and compounds that make up these half-reactions: (a) Which element is the weakest oxidizing agent? (b) Which ion or H 2 X is the weakest reducing agent? (c) Which of the elements listed is (are) capable of oxidizing to O 2 ? (d) Which of these elements listed is (are) capable of oxidizing to S? (e) Is O 2 capable of oxidizing I − to I 2 , in acid solution? (f) Is S capable of oxidizing I − to I 2 ? (g) Is the reaction H 2 S(aq) + Se(s) → H 2 Se(aq) + S(s) product-favored at equilibrium? (h) Is the reaction H 2 S(aq) + I 2 (s) → 2 H + (aq) + 2 I − (aq) + S(s) product-favored at equilibrium?

Interpretation:

The element which is the weakest oxidizing agent has to be determined.

Concept introduction:

Under certain conditions a cell potential is measured it is called as standard potential (Ecello).

Standard potential (Ecello) can be calculated by the following formula.

Ecello=Ecathodeo-Eanodeo

The Ecello value is positive, the reaction is predicted to be product favoured at equilibrium.

The Ecello value is negative, the reaction is predicted to be reactant favoured at equilibrium.

Electrochemical series:

It is a decreasing order of the reduction potentials. The most positive E0 are placed in the top in the electrochemical series, it has greater tendency for reduction and lower tendency of oxidation. And the most negative E0 values of elements are placed in the bottom of the series.

Let’s write the reduction potential of each of the following non-metal ions.

F2+2e-  →2F-                ; E0= + 2.87 VCl2+2e- →2Cl-             ; E0= + 1.36 VBr2+2e- →2Br-             ; E0= + 1.08 VI2+2e- →2I-                  ; E0= + 0.535 V

Further,

O2+4H++ 4e- →2H2O ; E0= + 1.229 VS +2H++ 2e- →H2S     ; E0= + 0.14 VSe + 2H++2e- →H2Se  ; E0 = - 0.40 V

Let’s write the reduction potential of each of the following non-metal ions.

F2+2e-  →2F-                ; E0= + 2.87 VCl2+2e- →2Cl-             ; E0= + 1.36 VBr2+2e- →2Br-             ; E0= + 1.08 VI2+2e- →2I-                  ; E0= + 0

Interpretation:

The ion or HX which is the weakest oxidising agent has to be determined.

Concept introduction:

Under certain conditions a cell potential is measured it is called as standard potential (Ecello).

Standard potential (Ecello) can be calculated by the following formula.

Ecello=Ecathodeo-Eanodeo

The Ecello value is positive, the reaction is predicted to be product favoured at equilibrium.

The Ecello value is negative, the reaction is predicted to be reactant favoured at equilibrium.

Electrochemical series:

It is an decreasing order of the reduction potentials. The most positive E0 are placed in the top in the electrochemical series, it has greater tendency for reduction and lower tendency of oxidation. And the most negative E0 values of elements are placed in the bottom of the series.

Let’s write the reduction potential of each of the following non-metal ions.

F2+2e-  →2F-                ; E0= + 2.87 VCl2+2e- →2Cl-             ; E0= + 1.36 VBr2+2e- →2Br-             ; E0= + 1.08 VI2+2e- →2I-                  ; E0= + 0.535 V

Further,

O2+4H++ 4e- →2H2O ; E0= + 1.229 VS +2H++ 2e- →H2S     ; E0= + 0.14 VSe + 2H++2e- →H2Se  ; E0 = - 0.40 V

Interpretation:

The element which is capable of oxidizing H2O to O2 has to be determined.

Concept introduction:

Under certain conditions a cell potential is measured it is called as standard potential (Ecello).

Standard potential (Ecello) can be calculated by the following formula.

Ecello=Ecathodeo-Eanodeo

The Ecello value is positive, the reaction is predicted to be product favoured at equilibrium.

The Ecello value is negative, the reaction is predicted to be reactant favoured at equilibrium.

Electrochemical series:

It is an decreasing order of the reduction potentials. The most positive E0 are placed in the top in the electrochemical series, it has greater tendency for reduction and lower tendency of oxidation. And the most negative E0 values of elements are placed in the bottom of the series.

Let’s write the reduction potential of each of the following non-metal ions.

F2+2e-  →2F-                ; E0= + 2.87 VCl2+2e- →2Cl-             ; E0= + 1.36 VBr2+2e- →2Br-             ; E0= + 1.08 VI2+2e- →2I-                  ; E0= + 0.535 V

Further,

O2+4H++ 4e- →2H2O ; E0= + 1.229 VS +2H++ 2e- →H2S     ; E0= + 0.14 VSe + 2H++2e- →H2Se  ; E0 = - 0.40 V

Interpretation:

The element which is capable of oxidizing H2O to S has to be determined.

Concept introduction:

Under certain conditions a cell potential is measured it is called as standard potential (Ecello).

Standard potential (Ecello) can be calculated by the following formula.

Ecello=Ecathodeo-Eanodeo

The Ecello value is positive, the reaction is predicted to be product favoured at equilibrium.

The Ecello value is negative, the reaction is predicted to be reactant favoured at equilibrium.

Electrochemical series:

It is an decreasing order of the reduction potentials. The most positive E0 are placed in the top in the electrochemical series, it has greater tendency for reduction and lower tendency of oxidation. And the most negative E0 values of elements are placed in the bottom of the series.

Let’s write the reduction potential of each of the following non-metal ions.

F2+2e-  →2F-                ; E0= + 2.87 VCl2+2e- →2Cl-             ; E0= + 1.36 VBr2+2e- →2Br-             ; E0= + 1.08 VI2+2e- →2I-                  ; E0= + 0.535 V

Further,

O2+4H++ 4e- →2H2O ; E0= + 1.229 VS +2H++ 2e- →H2S     ; E0= + 0.14 VSe + 2H++2e- →H2Se  ; E0 = - 0.40 V

Interpretation:

It has to be identified whether O2 is capable of oxidizing I- to I2 in acid solution.

Concept introduction:

Under certain conditions a cell potential is measured it is called as standard potential (Ecello).

Standard potential (Ecello) can be calculated by the following formula.

Ecello=Ecathodeo-Eanodeo

The Ecello value is positive, the reaction is predicted to be product favoured at equilibrium.

The Ecello value is negative, the reaction is predicted to be reactant favoured at equilibrium.

Electrochemical series:

It is an decreasing order of the reduction potentials. The most positive E0 are placed in the top in the electrochemical series, it has greater tendency for reduction and lower tendency of oxidation. And the most negative E0 values of elements are placed in the bottom of the series.

Let’s write the reduction potential of each of the following non-metal ions.

F2+2e-  →2F-                ; E0= + 2.87 VCl2+2e- →2Cl-             ; E0= + 1.36 VBr2+2e- →2Br-             ; E0= + 1.08 VI2+2e- →2I-                  ; E0= + 0.535 V

Further,

O2+4H++ 4e- →2H2O ; E0= + 1.229 VS +2H++ 2e- →H2S     ; E0= + 0.14 VSe + 2H++2e- →H2Se  ; E0 = - 0.40 V

Interpretation:

It has to be identified whether S is capable of oxidizing I- to I2.

Concept introduction:

Under certain conditions a cell potential is measured it is called as standard potential (Ecello).

Standard potential (Ecello) can be calculated by the following formula.

Ecello=Ecathodeo-Eanodeo

The Ecello value is positive, the reaction is predicted to be product favoured at equilibrium.

The Ecello value is negative, the reaction is predicted to be reactant favoured at equilibrium.

Electrochemical series:

It is an decreasing order of the reduction potentials. The most positive E0 are placed in the top in the electrochemical series, it has greater tendency for reduction and lower tendency of oxidation. And the most negative E0 values of elements are placed in the bottom of the series.

Let’s write the reduction potential of each of the following non-metal ions.

F2+2e-  →2F-                ; E0= + 2.87 VCl2+2e- →2Cl-             ; E0= + 1.36 VBr2+2e- →2Br-             ; E0= + 1.08 VI2+2e- →2I-                  ; E0= + 0.535 V

Further,

O2+4H++ 4e- →2H2O ; E0= + 1.229 VS +2H++ 2e- →H2S     ; E0= + 0.14 VSe + 2H++2e- →H2Se  ; E0 = - 0.40 V

Interpretation:

It has to be identified whether the reaction H2S(aq) + Se(s) →H2Se(aq) + S(s) is product –favoured at equilibrium.

Concept introduction:

Under certain conditions a cell potential is measured it is called as standard potential (Ecello).

Standard potential (Ecello) can be calculated by the following formula.

Ecello=Ecathodeo-Eanodeo

The Ecello value is positive, the reaction is predicted to be product favoured at equilibrium.

The Ecello value is negative, the reaction is predicted to be reactant favoured at equilibrium.

Electrochemical series:

It is an decreasing order of the reduction potentials. The most positive E0 are placed in the top in the electrochemical series, it has greater tendency for reduction and lower tendency of oxidation. And the most negative E0 values of elements are placed in the bottom of the series.

Let’s write the reduction potential of each of the following non-metal ions.

F2+2e-  →2F-                ; E0= + 2.87 VCl2+2e- →2Cl-             ; E0= + 1.36 VBr2+2e- →2Br-             ; E0= + 1.08 VI2+2e- →2I-                  ; E0= + 0.535 V

Further,

O2+4H++ 4e- →2H2O ; E0= + 1.229 VS +2H++ 2e- →H2S     ; E0= + 0.14 VSe + 2H++2e- →H2Se  ; E0 = - 0.40 V

Interpretation:

It has to be identified whether the reaction H2S(aq) + I2(s) →2H+(aq) + 2I-(aq) is product –favoured at equilibrium.

Concept introduction:

Under certain conditions a cell potential is measured it is called as standard potential (Ecello).

Standard potential (Ecello) can be calculated by the following formula.

Ecello=Ecathodeo-Eanodeo

The Ecello value is positive, the reaction is predicted to be product favoured at equilibrium.

The Ecello value is negative, the reaction is predicted to be reactant favoured at equilibrium.

Electrochemical series:

It is an decreasing order of the reduction potentials. The most positive E0 are placed in the top in the electrochemical series, it has greater tendency for reduction and lower tendency of oxidation. And the most negative E0 values of elements are placed in the bottom of the series.

Let’s write the reduction potential of each of the following non-metal ions.

F2+2e-  →2F-                ; E0= + 2.87 VCl2+2e- →2Cl-             ; E0= + 1.36 VBr2+2e- →2Br-             ; E0= + 1.08 VI2+2e- →2I-                  ; E0= + 0.535 V

Further,

O2+4H++ 4e- →2H2O ; E0= + 1.229 VS +2H++ 2e- →H2S     ; E0= + 0.14 VSe + 2H++2e- →H2Se  ; E0 = - 0.40 V