ELECTROCHEMISTRY QUESTIONS AND ANSWERS
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It is important to recognize the subscript changes the amount of elements in the compound.
Using the known rules, we know that O is -2 and Mn, since it is in group 2 would be +2.
Mn= 2 x 3= +6 and
O= -2 x 4 x 2= -16
P= 2 x 5= 10
The oxidation number of hydrogen in AlH3 is - CORRECT ANSWERS -1
AlH3
H= -1 x 3= -3
Al= +3
In Sn (s) + 2HCl (aq) ⟶ SnCl2 (aq) + H2 (g), what is being oxidized and what is being reduced? -
CORRECT ANSWERS Sn is being oxidized, H2 is being reduced.
1. Assign oxidation numbers to all atoms in the equation and ignore the coefficients in the
equation.
Sn (s) + 2HCl (aq) ⟶ SnCl2 (aq) + H2 (g)
0 +1 -1 +2 -1 0
2. Compare oxidation numbers from the reactant side to the product side of the equation. If a
redox reaction has occurred, you will find that the oxidation numbers of two (no more/no less)
elements have changed from the reactant side to the product side. The element oxidized is the
one whose oxidation number increased. The element reduced is the one whose oxidation
number decreased.
,ELECTROCHEMISTRY QUESTIONS AND ANSWERS
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Sn= 0 ⟶ Sn = +2, tin is oxidized
H= +1 ⟶ H= 0=, hydrogen is reduced
Is ZnCO3 (s) ⟶ ZnO (s) + CO2 (g) a redox reacrtion? - CORRECT ANSWERS No, nothing is being
oxidized or reduced.
2 Ga (l) + 3 Br2 (l) ⟶ 2 GaBr3 (s)
In this reaction, what is the oxidizing agent and what is the reducing agent? - CORRECT
ANSWERS Br2 is the oxidizing agent
Ga is the reducing agent
1. Assign oxidation numbers to each compound in the reaction.
2 Ga (l) + 3 Br2 (l) ⟶ 2 GaBr3 (s)
0 0 +3 -1
2. Compare oxidation numbers from reactant to products.
Ga= 0 ⟶ Ga= +3, Gallium is oxidized, therefore it is the reducing agent since the electrons it
loses reduced the charge of Bromine.
Br= 0 ⟶ Br= -1, Bromine is reduced, therefore it is the oxidizing agent since the electrons it
gains are a result of Gallium losing electrons.
For this reaction, which is the correct unbalanced oxidation half reaction?
, ELECTROCHEMISTRY QUESTIONS AND ANSWERS
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WITH CORRECT DETAILED/VERIFIED ANSWERS BEST
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Al (s) + Ni^2+ (aq) ⟶Ni (s) + Al^3+ (aq)
A. Al (s) ⟶ Al^3+ (aq)
B. Ni^2+ (aq) ⟶ Al^3+ (aq)
C. Ni (s) ⟶ Ni^2+ (aq)
D. Ni^2+ ⟶ (aq) Ni (s)
E. Al (s) ⟶ Ni (s)
F. Al^3+ (aq) ⟶ Al (s) - CORRECT ANSWERS A. Al (s) ⟶ Al3+ (aq)
1. Assign oxidation numbers to all the elements in the reaction.
Al (s) + Ni2+ (aq) ⟶ Ni (s) + Al3+ (aq)
0 2+ 0 3+
2. Aluminum is being oxidized so that will be the oxidation half reaction.
Al (s) ⟶ Al^3+ (aq)
For this reaction, what is the coefficient of Al (s) in the overall balanced equation?
Al (s) + Ni^2+ (aq) ⟶Ni (s) + Al^3+ (aq)
A. 1
2024/2025 LATEST UPDATED A COMPLETE SOLUTION
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GRADED A+ FOR SUCCESS
It is important to recognize the subscript changes the amount of elements in the compound.
Using the known rules, we know that O is -2 and Mn, since it is in group 2 would be +2.
Mn= 2 x 3= +6 and
O= -2 x 4 x 2= -16
P= 2 x 5= 10
The oxidation number of hydrogen in AlH3 is - CORRECT ANSWERS -1
AlH3
H= -1 x 3= -3
Al= +3
In Sn (s) + 2HCl (aq) ⟶ SnCl2 (aq) + H2 (g), what is being oxidized and what is being reduced? -
CORRECT ANSWERS Sn is being oxidized, H2 is being reduced.
1. Assign oxidation numbers to all atoms in the equation and ignore the coefficients in the
equation.
Sn (s) + 2HCl (aq) ⟶ SnCl2 (aq) + H2 (g)
0 +1 -1 +2 -1 0
2. Compare oxidation numbers from the reactant side to the product side of the equation. If a
redox reaction has occurred, you will find that the oxidation numbers of two (no more/no less)
elements have changed from the reactant side to the product side. The element oxidized is the
one whose oxidation number increased. The element reduced is the one whose oxidation
number decreased.
,ELECTROCHEMISTRY QUESTIONS AND ANSWERS
2024/2025 LATEST UPDATED A COMPLETE SOLUTION
WITH CORRECT DETAILED/VERIFIED ANSWERS BEST
GRADED A+ FOR SUCCESS
Sn= 0 ⟶ Sn = +2, tin is oxidized
H= +1 ⟶ H= 0=, hydrogen is reduced
Is ZnCO3 (s) ⟶ ZnO (s) + CO2 (g) a redox reacrtion? - CORRECT ANSWERS No, nothing is being
oxidized or reduced.
2 Ga (l) + 3 Br2 (l) ⟶ 2 GaBr3 (s)
In this reaction, what is the oxidizing agent and what is the reducing agent? - CORRECT
ANSWERS Br2 is the oxidizing agent
Ga is the reducing agent
1. Assign oxidation numbers to each compound in the reaction.
2 Ga (l) + 3 Br2 (l) ⟶ 2 GaBr3 (s)
0 0 +3 -1
2. Compare oxidation numbers from reactant to products.
Ga= 0 ⟶ Ga= +3, Gallium is oxidized, therefore it is the reducing agent since the electrons it
loses reduced the charge of Bromine.
Br= 0 ⟶ Br= -1, Bromine is reduced, therefore it is the oxidizing agent since the electrons it
gains are a result of Gallium losing electrons.
For this reaction, which is the correct unbalanced oxidation half reaction?
, ELECTROCHEMISTRY QUESTIONS AND ANSWERS
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WITH CORRECT DETAILED/VERIFIED ANSWERS BEST
GRADED A+ FOR SUCCESS
Al (s) + Ni^2+ (aq) ⟶Ni (s) + Al^3+ (aq)
A. Al (s) ⟶ Al^3+ (aq)
B. Ni^2+ (aq) ⟶ Al^3+ (aq)
C. Ni (s) ⟶ Ni^2+ (aq)
D. Ni^2+ ⟶ (aq) Ni (s)
E. Al (s) ⟶ Ni (s)
F. Al^3+ (aq) ⟶ Al (s) - CORRECT ANSWERS A. Al (s) ⟶ Al3+ (aq)
1. Assign oxidation numbers to all the elements in the reaction.
Al (s) + Ni2+ (aq) ⟶ Ni (s) + Al3+ (aq)
0 2+ 0 3+
2. Aluminum is being oxidized so that will be the oxidation half reaction.
Al (s) ⟶ Al^3+ (aq)
For this reaction, what is the coefficient of Al (s) in the overall balanced equation?
Al (s) + Ni^2+ (aq) ⟶Ni (s) + Al^3+ (aq)
A. 1
