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WorksheetsRedox (25 q)
Total questions: 25
Worksheet time: 13mins
Which changes occur when Pt2+ is reduced?
The Pt2+ gains electrons and its oxidation number increases.
The Pt2+ gains electrons and its oxidation number decreases.
The Pt2+ loses electrons and its oxidation number increases.
The Pt2+ loses electrons and its oxidation number decreases.
Given the balanced equation representing a redox reaction:
2Al + 3Cu2+ --> 2Al3+ + 3Cu
Which statement is true about this reaction?
Each Al loses 2e- and each Cu2+ gains 3e-
Each Al loses 3e- and each Cu2+ gains 2e-
Each Al3+ gains 2e- and each Cu loses 3e-
Each Al3+ gains 3e- and each Cu loses 2e-
Which change in oxidation number indicates oxidation?
–1 to +2
–1 to –2
+2 to –3
+3 to +2
In which compound does chlorine have the highest oxidation number?
NaClO
NaClO2
NaClO3
NaClO4
What is the oxidation number of sulfur in Na2S2O3?
-1
+2
+6
+4
What is the oxidation number of iodine in KIO4?
+1
-1
+7
-7
Which particles are gained and lost during a redox reaction?
Electrons
Protons
Neutrons
Positrons
Which half-reaction correctly represents oxidation?
Sn+2 + 2e- --> Sn0
Sn+2 --> 2e- + Sn0
Sn+4 +2e- --> Sn2+
Sn+2 --> +2e- + Sn+4
Which species is oxidized when the switch is closed?
Mg (s)
Mg+2 (aq)
Ag (s)
Ag+(aq)
In a chemical cell composed of two half-cells, ions are allowed to flow from one half-cell to another by means of
electrodes
a voltmeter
an external conductor
a salt bridge
Which half-reaction equation represents the reduction of a potassium ion?
K+ + e– --> K
K + e– --> K+
K+ --> K + e–
K --> K+ + e–
Which is a redox reaction?
Mg + 2 HCl --> MgCl2 + H2
Mg(OH)2 + 2 HCl --> MgCl2 + 2 H2O
Mg2+ (aq) + 2 OH– (aq) --> Mg(OH)2
MgCl2 + 6 H2O --> MgCl2•6 H2O
Which half-reaction for the reduction of Al 3+ to Al is correctly balanced?
Al3+ + 3e– --> Al
Al3+ + 3e– --> 3 Al
Al3+ --> Al + 3e–
Al3+ --> 3 Al + 3e–
Compared to the amount of mass and total charge at the beginning of a redox reaction, the amount of mass and total charge upon completion of the reaction is
Less
Greater
The same
In an electrolytic cell, the negative electrode is called the
anode, at which oxidation occurs
anode, at which reduction occurs
cathode, at which oxidation occurs
cathode, at which reduction occurs
Which statement is true about oxidation and reduction in an electrochemical cell?
Both occur at the anode.
Both occur at the cathode.
Oxidation occurs at the anode and reduction occurs at the cathode.
Oxidation occurs at the cathode and reduction occurs at the anode.
A voltaic cell differs from an electrolytic cell in that in a voltaic cell
neither oxidation nor reduction occurs
energy is required for the reaction to occur
energy is produced when the reaction occurs
both oxidation and reduction occur
A voltaic cell spontaneously converts
chemical energy to electrical energy
nuclear energy to electrical energy
electrical energy to chemical energy
electrical energy to nuclear energy
Which simple oxidation-reduction reaction is not correctly balanced?
Iron corrodes according to the equation
4 Fe + 3 O2 → 2 Fe2O3 . This redox process occurs because
iron loses electrons and is oxidized
oxygen loses electrons and is reduced
iron gains electrons and is reduced
oxygen gains electrons and is oxidized
When the switch is closed, electrons flow from
Al(s) to Ni(s)
Ni(s) to Al(s)
Al3+(aq) to Ni2+(aq)
Ni2+(aq) to Al3+(aq)
When the switch is closed, what occurs?
Pb is oxidized and electrons flow to the Zn electrode.
Pb is reduced and electrons flow to the Zn electrode.
Zn is oxidized and electrons flow to the Pb electrode.
Zn is reduced and electrons flow to the Pb electrode.
Given the balanced equation representing a reaction occurring in an electrolytic cell:
2NaCl → 2Na + Cl2 (g)
Where is Na produced in the cell?
at the anode, where oxidation occurs
at the anode, where reduction occurs
at the cathode, where oxidation occurs
at the cathode, where reduction occurs
If the oxidation state of a species changes from 0 before a redox reaction to 2 after the reaction, what happened to it?
It was decomposed
It was a spectator ion
It gained 2 electrons
It lost 2 electrons
Where does reduction occur in a voltaic cell?
Load
Anode
Cathode
Salt bridge
