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Descripción: Handbook of electrochemistry
Need to pass the Series 7 exam? This is the best thing that helped me. Here are 117 Test questions focusing on the Options Market. Example: 63. A covered call position is A. the simultaneous p...
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Strong reducing agents
Very reactive with H2O (cold & hot) forming metal hydroxide and hydroxide and H2(g), also vigorously react with acids (dilute & concentrated) concentrated) producing metal salt and H2 gas.
No reactions occur with water but but react slightly with acids producing metal salts and hydrog en gas gas (an exception is HNO 3)
Li K Ba Ca Na Mg Al Mn Zn Cr Fe Cd Co Ni Sn Pb
H2 Cu Ag Hg Pt Au
Strong oxidizing a ents
Reactive with water steam forming respective metal hydroxide and hydroxide and H2, also quite reactive with dilute and concentrated acids to produce salt and H2 gas (an exception is HNO3).
None of the metals below can displace H 2 in the reactions with acids. The only reactions possible are the reactions with acids that have strong oxidizing ability such as conc. H 2SO4 and dilute and conc. HNO 3.
Reactivity series of metals Activity of some non-metals and groups strong ability to oxidize
F ; Cl ; Br ; I ; OH ; NO3 ;
SO42
; PO4
3
strong ability to reduce
MULTIPLE CHOICE QUESTIONS 1. Iron reacts with water steam to produce A C
iron(II) oxide and releases hydrogen gas iron(II) hydroxide and releases hydrogen gas
B D
iron(III) oxide and water iron(II) hydroxide only
2. When metallic magnesium reacts with dilute hydrochlor ic acid it produces A C
magnesium chloride and water magnesium oxide only
3. Copper and hydroc hloric acid give A copper(II) hydroxide + oxygen C copper(II) chloride + oxygen
D
magnesium chloride and hydrogen there would be no reaction
B D
copper hydrate only no reaction
B
4. The reaction of i ron and copper(II) sulphate describes as A double displacement reaction where metallic iron displaces copper(II) ions B double displacement reaction where copper displaces iron C single displacement reaction where the iron displaces the copper (II) ions D no reaction 5. A reaction is given: 3Sn4+(aq) + 2Cr(s)
→
3Sn2+(aq) + 2Cr 3+(aq)
Which half-reaction represents a reduction ? A Sn4+(aq) + 2e- → Sn2+(aq) B 3+ C Cr(s) − 3e → Cr (aq) D
Sn2+(aq) − 2eCr 3+(aq) + 3e-
Sn4+(aq) → Cr(s) →
6. In an electrol ytic cell, the negative electro de is called A anode, at which oxidation occurs B anode, at which reduction occurs C cathode, at which oxidation occurs D cathode, at which reduction occurs 7. The diagram below represents an electrochemical cell. What happens when the switch A Zn is reduced B Cu is oxidized C Electrons flow from Cu to Zn D Electrons flow from Zn to Cu.
is
closed?
8. What is the purpose of a salt bridge in galvanic cells? A It is an anode. B It is a cathode. C It permits the migration of ions between the half-cells. D It permits the mixing of solutions between the half-cells. 9. Which statement of these is not true? A The anode in electrolytic cell has positive charge; B The reduction processes always occur in the cathode; C The lead storage batteries work as galvanic cells when charging; D The electrolytic cells are reverse from galvanic.
10. What species acts as oxidizing agent in the redox reaction b elow? Mg(s) + CuSO4(aq) MgSO4(aq) + Cu(s) A
Cu(s)
B
Cu2+(aq)
C
Mg(s)
Mg2+(aq)
D
11. What is i ndicated when a chemical cell's volt age has dropped to zero? A The concentration of the reactants has increased B The concentration of the products has decreased C The cell reaction has reached equilibrium D The cell reaction has completely stopped 12. Which of the following ion s is the weakest oxidi zing agent? A Au3+ B Cr 3+ C Hg2+
D
Ba2+
D
Cu(s)
13. The following redox reaction is given: 2Cr(s) + 3Cu2+(aq) → 3Cr 3+(aq) + 3Cu(s) Which reaction occu rs at the cathode in an electrochemical cell? A reduction of Cu2+(aq) B reduction of Cu(s) 3+ C oxidation of Cr (aq) D oxidation of Cr(s) 14. The follo wing cell reaction best describes el. current
2H2O(l) A B C D
⎯⎯⎯→
2H2(g) + O2(g)
an electrolytic cell in which an exothermic reaction occurs an electrolytic cell in which an endothermic reaction occurs a galvanic cell in which an exothermic reaction occurs a galvanic cell in which an endothermic reaction occurs
15. What species is reducti on agent in the following reaction? Pb(s) + Cu2+(aq) Pb2+(aq) + Cu(s) A
Pb2+(aq)
B
Cu2+(aq)
C
Pb(s)
16. The overall reaction that happens in the lead storage battery is: Pb(s) + PbO2(s) + 4H+(aq) + 2SO42 (aq) −
2PbSO4(s) + 2H2O(l)
⇌
What is happening during charge the battery? A Pb is oxidized to Pb2+ B Pb4+ is oxidized to Pb 2+ C Pb2+ is reduced to Pb 4+ D Pb2+ is reduced to Pb 17. Which one of these will not react? hot
A
Mg(s) + H2O(l)
B
Ca(s) + HCl(aq)
C
Cu + 2HCl
→
Mg(OH)2(aq) + H2(g)
⎯→
CaCl2(aq) + H2(g)
→
CuCl2(aq) + H2(g) conc.
D
2Ag + 2H2SO4 ⎯→ Ag2SO4(aq) + SO2(g) + 2H2O(l)
18. The purpos e of the salt bridge in the Daniel cell is A to provide migration of Zn2+ and SO42 ions from one to the other half-cell; B to oxidize the Zn anode to Zn 2+ C to provide migration of electrons from anode to cathode; D to reduce the Cu 2+ ions to elemental copper where is deposited. −
19. Which of th e followin g metal ions can easily be reduced into elemental for m? A Ag+ B Cu2+ C Na+ D Pb2+ 20. The fuel cell forms the following produc t: A H2 B O2 C
H2O
D
H2SO4
21. Find th e reactio n that takes place at the anode in the Leclanché (dry) cell. A Cu2+(aq) + 2 e → Cu(s) −
B
MnO2(s) + 2NH4+(aq) + 2e
C
Zn(s)
D
Pb(s) + SO42 (aq)
−
−
→
Mn2O3 + 2NH3(g) + H2O(l)
2e = Zn2+(aq) −
−
→
PbSO4(s)
22. In some galvanic cell the overall reaction happens is: Zn(s) + Ag+(aq)
→
Zn2+(aq) + Ag(s)
Which of t he follow ing half-reaction s takes place in the anode? A Ag(s) − e → Ag+(aq) B Zn2+(aq) + 2e −
C
Ag+(aq) + e
−
Ag(s)
→
D
Zn(s)
−
−
2e
−
→
→
Zn(s)
Zn2+(aq)
23. In the lead storage battery, _________ is a joint product of reactions taking place on both electrodes. A Pb B PbO2 C PbSO4 D H2SO4 24. What species move toward the cathode? A anions B both cations and anions C cations D electrons 25. Which of the following equation represents the half-reaction happening in the electro chemical cell, Al(s) | Al 3+(aq) || Cu 2+(aq) | Cu(s)? −
2Aln(s)
C
2Al(s) + 3Cu2+(aq)
−
6e
Al3+(aq)
A
→
→
2Al3+(aq) + 3Cu(s)
B
3Cu2+(aq) + 6e
D
none of the above
−
Cu(s)
→
26. What are the products obt ained at the anode and cathode during electrol ysis of sodium chloride in an electrolytic cell? A Na(s) and Cl2(g) B Na(s), water and O2(g) C H2(g), H2O(l) and O2(g) D H2(g) and Cl 2(g) 27. In which case will th e oxygen gas be evolved at the anode? A electrolysis of KCl B electrolysis of Na 2SO4 C electrolysis of NaBr D electrolysis of CuCl 2 28. When copper reacts wit h dilut e nitric acid, the obtained product s are A Cu(NO3)2 and H2 B Cu(NO3)2, NO and H 2O C Cu(NO3)2, NO2 and H2O D no reaction 29. When Zn ro d is immersed in an aqueous copper(II) sulphate the reaction w ill b e A synthesis B double displacement C single replacement D there would be no reaction 30. The rust i s described by the formu la: A Fe2O3 B Fe2O3 ⋅ xH2O
