Deck 17: Oxidationreduction

Question 1

In an electrolytic cell

A)a chemical reaction occurs spontaneously and releases energy as electricity.
B)electricity causes a chemical reaction to occur.
C)a physical change occurs spontaneously and releases energy as electricity.
D)electricity causes a physical change to occur.

Answer 1

electricity causes a chemical reaction to occur.

Question 2

Which species is reduced in the following equation? 2 Ca + O₂ $\rarr$ 2 CaO

A)Ca
B)O₂
C)Ca⁺²
D)O^-2

Answer 2

O₂

Question 3

During a redox reaction,the oxidation number of the species reduced will

A)increase.
B)decrease.
C)remain the same.

Answer 3

decrease.

Question 4

The reducing agent is

A)the species that is reduced.
B)the species with a negative charge.
C)the species that loses electrons.
D)the species that gains electrons.

Question 5

What is the oxidation number of oxygen in OF₂?

A)0
B)+2
C)-1
D)-2

Question 6

What always occurs at the cathode in an electrolytic cell?

A)Protons are gained
B)Protons are lost
C)Electrons are gained
D)Electrons are lost

Question 7

What is the oxidation number of manganese in MnO₂?

A)+2
B)-4
C)+4
D)0

Question 8

Reduction is the

A)gain of protons.
B)loss of protons.
C)gain of electrons.
D)loss of electrons.

Question 9

Which species is oxidized in the following equation? 2 Na + Cl₂ $\rarr$ 2 NaCl

A)Na
B)Cl₂
C)Na⁺¹
D)Cl^-1

Question 10

In a voltaic cell

A)a chemical reaction occurs spontaneously and releases energy as electricity.
B)electricity causes a chemical reaction to occur.
C)a physical change occurs spontaneously and releases energy as electricity.
D)electricity causes a physical change to occur.

Question 11

What always travels through the external circuit (wire)in a voltaic cell?

A)Protons
B)Electrons
C)Neutrons
D)Ions

Question 12

What is the oxidation number of bromine in Br₂?

A)0
B)-1
C)+7
D)-5

Question 13

The oxidizing agent is

A)the species that is oxidized.
B)the species with a positive charge.
C)the species that loses electrons.
D)the species that gains electrons.

Question 14

What always occurs at the anode in an electrolytic cell?

A)Protons are gained
B)Protons are lost
C)Electrons are gained
D)Electrons are lost

Question 15

What always travels through the salt bridge in a voltaic cell?

A)Protons
B)Electrons
C)Neutrons
D)Ions

Question 16

During a redox reaction,the oxidation number of the species oxidized will

A)increase.
B)decrease.
C)remain the same.

Question 17

What is the oxidation number of chromium in Cr₂O₇^-2?

A)+12
B)0
C)+6
D)-4

Question 18

Oxidation is the

A)gain of protons.
B)loss of protons.
C)gain of electrons.
D)loss of electrons.

Question 19

What is the oxidation number of chlorine in HClO₄?

A)0
B)+7
C)-1
D)-3

Question 20

What is the oxidation number of oxygen in H₂O₂?

A)-2
B)0
C)+2
D)-1

Question 21

How many moles of electrons are gained when four moles of fluorine atoms are reduced tofluoride ions?

A)1
B)2
C)4
D)8

Question 22

Which occurs when a calcium atom is oxidized?

A)Two protons are lost
B)Two protons are gained
C)Two electrons are lost
D)Two electrons are gained

Question 23

In this chemical process,the oxidation numbers of aluminum on the reactant and the product are: 2 Al₂O₃ $\rarr$ 4 Al + 3 O₂

A)+2,+3
B)+3,0
C)+2,+4
D)0,+4

Question 24

How many moles of electrons are lost when two moles of aluminum atoms are oxidized toaluminum ions?

A)2
B)3
C)6
D)9

Question 25

Which species is oxidized in the following equation? 2 H₂O $\rarr$ 2 H₂ + O₂

A)H₂
B)O₂
C)H⁺¹
D)O^-2

Question 26

Which species is the oxidizing agent in the following equation?
2 H₂O $\rarr$ 2 H₂ + O₂

A)H⁺¹
B)O^-2
C)H₂
D)O₂

Question 27

How many moles of electron are lost when one mole of barium atoms is oxidized to barium ions?

A)2
B)1
C)4
D)3

Question 28

Which is the correct reduction half-reaction for the following equation?
Zn + 2 HCl $\rarr$ ZnCl₂ + H₂

A)Zn $\rarr$ Zn⁺² + 2 e^-1
B)Zn⁺² + 2 e^-1 $\rarr$ Zn
C)2 H⁺¹ + 2 e^-1 $\rarr$ H₂
D)H₂ $\rarr$ 2 H⁺¹ + 2 e^-1

Question 29

Which is the correct reduction half-reaction for the following equation?
Ba + CuO $\rarr$ BaO + Cu

A)Ba⁺² + 2 e^-1 $\rarr$ Ba
B)Cu $\rarr$ Cu⁺² + 2 e^-1
C)Ba $\rarr$ Ba⁺² + 2 e^-1
D)Cu⁺² + 2 e^-1 $\rarr$ Cu

Question 30

Which species is the reducing agent in the following equation?
2 Al₂O₃ $\rarr$ 4 Al + 3O₂

A)Al⁺³
B)O^-2
C)Al
D)O₂

Question 31

Which is the correct oxidation half-reaction for the following equation?
Zn + 2 Ag⁺¹ $\rarr$ Zn⁺² + 2 Ag

A)Ag $\rarr$ Ag⁺¹ + 1 e^-1
B)Ag⁺¹ + 1 e^-1 $\rarr$ Ag
C)Zn⁺² + 2 e^-1 $\rarr$ Zn
D)Zn $\rarr$ Zn⁺² + 2 e^-1

Question 32

Which species is the reducing agent in the following equation?
2 Ca + O₂ $\rarr$ 2 CaO

A)Ca
B)O₂
C)Ca⁺²
D)O^-2

Question 33

In a redox reaction,the total number of electrons gained is

A)greater than the total number of electrons lost.
B)less than the total number of electrons lost.
C)equal to the number of electrons lost.
D)not related at all to the number of electrons lost.

Question 34

How many moles of electrons are gained when three moles of oxygen atoms are reduced tooxide ions?

A)2
B)3
C)4
D)6

Question 35

Which occurs when an oxygen atom is reduced?

A)Two protons are gained
B)Two protons are lost
C)Two electrons are gained
D)Two electrons are lost

Question 36

A redox reaction is a reaction in which

A)only oxidation occurs.
B)only reduction occurs.
C)both reduction and oxidation occur.
D)neither oxidation nor reduction occur.

Question 37

Which occurs when a sodium atom is oxidized?

A)One electron is gained
B)One electron is lost
C)One proton is gained
D)One proton is lost

Question 38

Which occurs when a chlorine atom is reduced?

A)One electron is gained
B)One electron is lost
C)One proton is gained
D)One proton is lost

Question 39

Which is the correct oxidation half-reaction for the following equation?
2 Na + 2 H₂O $\rarr$ 2 NaOH + H₂

A)Na⁺¹ + e^-1 $\rarr$ Na
B)Na $\rarr$ Na⁺¹ + e^-1
C)2 H⁺¹ + 2 e^-1 $\rarr$ H₂
D)H₂ $\rarr$ 2 H⁺¹ + 2 e^-1

Question 40

Which species is the oxidizing agent in the following equation?
2 Na + Cl₂ $\rarr$ 2 NaCl

A)Na
B)Cl₂
C)Na⁺¹
D)Cl^-1

Question 41

What is the oxidation number of carbon in CO₂?

A)-4
B)-2
C)+2
D)+4

Question 42

Which element forms ions that will migrate toward the cathode in an electrolytic cell?

A)Bromine
B)Oxygen
C)Iodine
D)Silver

Question 43

What is the oxidation number of oxygen in MgCrO₄?

A)-2
B)0
C)+2
D)-1

Question 44

Which element forms ions that will migrate toward the anode in an electrolytic cell?

A)Silver
B)Chlorine
C)Copper
D)Sodium

Question 45

What is the oxidation number of sulfur in H₂SO₄?

A)+2
B)+4
C)+6
D)-2

Question 46

Which species is oxidized in the following equation?
2 Na + 2 H⁺¹ $\rarr$ 2 Na⁺¹ + H₂

A)Na⁺¹
B)H₂
C)Na
D)H⁺¹

Question 47

Which element forms ions that will migrate toward the cathode in an electrolytic cell?

A)Copper
B)Chlorine
C)Oxygen
D)Fluorine

Question 48

What is the oxidation number of hydrogen in NH₃?

A)-3
B)-1
C)+1
D)+3

Question 49

What is the oxidation number of iron in Fe₂O₃?

A)+2
B)+4
C)+3
D)+6

Question 50

In the following reaction,the copper(II)ions Ni + Cu⁺² $\rarr$ Ni⁺² + Cu

A)gain electrons.
B)lose electrons.
C)gain protons.
D)lose protons.

Question 51

Which element forms ions that will migrate toward the anode in an electrolytic cell?

A)Copper
B)Potassium
C)Bromine
D)Gold

Question 52

In the following reaction,the chlorine atoms 2 Na + Cl₂ $\rarr$ 2 NaCl

A)gain electrons.
B)lose electrons.
C)gain protons.
D)lose protons.

Question 53

In the following redox reaction F₂(g)+ 2NaI(aq) I₂(s)+ 2NaF(aq)
The total number of moles of electrons transferred between one mole of the oxidizing and reducing agents is

A)one mole
B)three moles
C)0.5 mole
D)two moles

Question 54

When the following reaction is balanced in basic media KOH + Cl₂ KCl + KClO
Moles of water molecules will appear on the side of the balanced equation.

A)two,reactant
B)four,product
C)two,product
D)four,reactant

Question 55

Which is conserved in all oxidation-reduction reactions?

A)Mass,only
B)Charge,only
C)Both mass and charge
D)Neither mass nor charge

Question 56

What is the oxidation number of hydrogen in H₂O₂?

A)-2
B)-1
C)+1
D)+2

Question 57

In the following reaction,the zinc atoms Zn + 2 Ag⁺¹ $\rarr$ Zn⁺² + 2 Ag

A)gain protons.
B)lose protons.
C)gain electrons.
D)lose electrons.

Question 58

In the following reaction,the hydrogen atoms 2 H₂ + O₂ $\rarr$ 2 H₂O

A)gain protons.
B)lose protons.
C)gain electrons.
D)lose electrons.

Question 59

What is the oxidation number of oxygen in O₂?

A)-2
B)-1
C)0
D)+2

Question 60

In the following redox reaction Fe₂O₃ + C 2Fe + CO₂
The total number of moles of electrons transferred between one mole of the oxidizing and reducing agents is

A)two moles
B)one mole
C)0.5 mole
D)three moles

Question 61

When the following reaction is balanced in acidic media Cu + Cu²⁺ + NO
One of the terms in the balanced equation will be:

A)3H₂O
B)8H⁺
C)2Cu²⁺
D)4H⁺

Question 62

Which of the following species will displace nickel from Ni(C₂H₃O₂)₂(aq):

A)Cu(s)
B)Hg(l)
C)Ag(s)
D)Na(s)

Question 63

In a voltaic cell,oxidation occurs at the

A)Anode
B)Cathode
C)Internal circuit
D)External circuit

Question 64

The products of the reaction between solid magnesium metal and water are

A)Mg(OH)₂(aq)and H₂(g)
B)MgO₂(aq)and H₂(g)
C)MgH₂(aq)+ O₂(g)
D)No reaction takes place.

Question 65

All the following are true for a galvanic cell except

A)Oxidation occurs at the cathode
B)A spontaneous reaction takes place in the cell
C)Cations are attracted to the cathode
D)The salt bridge allows the migration of ions

Question 66

In the electrolysis of fused (molten)sodium chloride,the product at the anode is

A)Na
B)Na⁺¹
C)Cl^-1
D)Cl₂

Question 67

Which of the following species will displace lead from Pb(NO₃)₂(aq):

A)Au
B)Hg
C)Cr³⁺
D)Ba

Question 68

In the electrolysis of fused (molten)sodium chloride,the product at the cathode is

A)Na⁺¹
B)Na
C)Cl^-1
D)Cl₂

Question 69

When the following equation is balanced in acidic media + S NO₂ + one of the terms in the balanced equation will be:

A)8H⁺
B)2H₂O
C)6H₂O
D)2NO₂

Question 70

Nitrogen has a +3 oxidation state in

A)N₂O
B)N₂O₃
C)N₂O₄
D)NO

Question 71

In MnCr₂O₇,the oxidation number of chromium is

A)+2
B)-2
C)+12
D)+6

Question 72

Which does not involve oxidation-reduction?

A)Burning sodium in chlorine
B)The chemical formation of iron(II)sulfide from its elements
C)Decomposition of potassium chlorate
D)Neutralization of sodium hydroxide by sulfuric acid

Question 73

In the electrolysis of fused (molten)calcium chloride,the product at the cathode is

A)Ca⁺²
B)Cl^-1
C)Cl₂
D)Ca

Question 74

Moving from the top to the bottom of the activity series of the metals

A)arranges the metals by increasing amount of electrons lost.
B)arranges the metals by decreasing ease of reduction.
C)arranges the metals by decreasing ease of oxidation.
D)arranges the metals by increasing reactivity.

Question 75

In an electrolytic cell the charge of the cathode is

A)Positive
B)Negative
C)Neutral

Question 76

In Ba(NO₃)₂,the oxidation number of nitrogen is

A)-3
B)-1
C)+4
D)+5

Question 77

Which is the principal characteristic of all redox reactions?

A)The formation of water
B)The formation of a gas or precipitate
C)An irreversible reaction
D)The transfer of electrons

Question 78

In a voltaic cell,reduction occurs at the

A)External circuit
B)Internal circuit
C)Cathode
D)Anode

Question 79

In the electrolysis of fused (molten)calcium chloride,the product at the anode is

A)Cl^-1
B)Cl₂
C)Ca⁺²
D)Ca

Question 80

The products of the reaction between iron metal and calcium chloride are

A)FeCl₂(aq)+ Ca(s)
B)No reaction takes place.
C)FeCl(aq)+ CaCl(aq)
D)CaFe(s)+ Cl₂(g)