Chapter 10: Electrochemistry
1: Which of the following reaction is possible at anode?
a) F2 —> 2F–
b) ½ O2 + 2H+ —> H2O
c) 2Cr3+ + 7H20 —> Cr2O72- + 14 H20
d) None of these
2:.Which one among the following is the strongest reducing agent
Fe2+ + 2e– —> Fe (-0.44V)
Ni2+ +2e– —> Ni (-O.25V)
Sn2+ +2e– —> Sn (-O.14V)
Fe3+ + e– —> Fe2+ (—0.77 V)
3: The cell reaction Of the galvanic cell given below is;
cu I cu2+ II Hg2+ I Hg
a) Hg+ cu2+ —> Hg2+ + Cu
b) Cu + Hg —> CuHg
c) Hg+ cu2+ —> Cu+ + Hg+
d) Cu + Hg2+ —> cu2+ + Hg
4: The oxide which is not reduced by hydrogen is
5: Consider the following cell reaction
Pb + 2Ag+ —> Pb2+ + 2Ag
If a cell is made based on this equation then
a) Lead will act as anode and Silver as cathode
b) Lead will act as cathode and silver as anode
c) Silver will act Cathode because it has greater reduction potential
d) Lead will act as anode because it has lesser reduction
6: Which one of the following reactions is a redox reaction?
a) Pb2++ 2Cl– —> PbCl2
b) NaOH + HCl —> NaCl + H2O
c) AgNO3 + HCl —> AgCl + HNO3
d) 2Al + 3Cl2 —> 2AlCl3
7: Which species is the oxidizing agent in the following reaction?
Cl2 + 2l– —> l2 + 2Cl–
8: In an electrochemical cell, electrons flow in which direction?
a) From the anode to cathode through the porous cup
b) From the cathode to anode through the external circuit
c) From the anode to cathode through the external circuit
d) From the cathode to anode through porous cup
9: Given the two following half reactions
Ni2+ + 2e– —> Ni Eo = -0.25
Hg+2 + 2e– —> Hg Eo= 0.885
Calculate Eo for the following reaction
a) -1.11 V
b) +0.61 V
c) +1.11 V
10: Which of the following substances is not an electrolyte?
a) Common salt
b) Sulphuric acid
c) Acetic acid
11: The conduction of electric current through the external circuit in an electrolytic cell is by
b) Negative ions only
c) positively charged metal ions only
d) both positively and negatively charged ions
12: The products of electrolysis of an aqueous solution of a slt
a) Cannot be predicted always
b) Can be predicted always without an experiment
c) Always include a metallic product
d) Include none of the above
13: The product obtained at the anode by the electrolysis of an aqueous solution of sulfuric acid is
d) No product is formed
14: Which of the following metals will not displace Cu from aqueous solution of CuSO4?
15: The most easily oxidizable species amongst the following is
16: Which of the following metals has the most negative value of standard electrode reduction potential?
17: In Daniel cell direction of electron flow is
a) Towards cathode
b) Towards anode
c) Towards Zinc Electrode
d) From copper to zinc electrode
18: Which of the following statements are true for a standard cell setup using the half cells below?
Ni2+ (aq)/ Ni Eored = -0.25V
Sn2+ (aq)/Sn Eored = -0.14V
a) Electrons flow in the external circuit from Sn to Ni.
B) The concentration 0f Sn2+ will decrease.
c) Oxidation occurs at the Sn terminal.
d) The cell cannot be formulated.
19: Among the following molecules, in which does bromine show the highest oxidation number?
20: The standard potential for the electrode reaction represented by the equation
Pb4+ + 2e- ↔ Pb2+
is +1.69 V. What may be deduced from this information alone?
a) Load (lV) compounds can act as oxidizing agents.
b) Load is more stable in +4 than +2 oxidation state.
c) Pb(SO4)2 will not exist,
d) None of the above
21: Which of the following statements about the reaction given below are correct?
l03. (aq) + 2l. (aq) +6H+ (aq) + 6Cl. (aq) —> 3lCl2. (aq)+ 3H2O (l)
a) The oxidation number of in the iodide ion l., changes from -1 to +2.
b) The oxidation number of iodine in the iodate ion, l03. (aq), changes from +5 to +1.
c) The oxidation number of chlorine in the iodide ion l., changes from -1 to -2.
d) Iodate ions are oxidized.
22: Which of the following compounds will not conduct electricity in its aqueous solution?
a) Carbon tetrachloride
b) Silver chloride
c) Sodium acetate
d) Sulphuric Acid
23: In an electrolytic cell Current flows
a) From cathode to anode in outer circuit
b) From cathode to anode inside the cell
c) From anode to cathode outside the cell
d) From anode to cathode inside the cell
24: The degree of ionization of a substance depends on
a) The size of solute molecules
b) The Nature Of vessel used
c) The Nature of solute molecules
d) The Quantity of electricity passed
25: Which of the following gas is produced at anode during electrolysis of aqueous sodium sulfate?
26: When a Zn piece is placed in CuS04 solution, gets precipitated because
a) Standard reduction potential of Zn is more than that of copper
b) Standard reduction of Zn is less than that of copper
c) Atomic no. of Zn is larger than that of Cu
d) Atomic no. of Zn is smaller than that of Cu
27: In an experimental set up for the measurement of e.m.f. of a half cell using a reference electrode and a salt bridge, when the Salt bridge is removed, the voltage
a) Does not change.
b) Decreases half the value.
c) Increases to a maximum
d) Drops to zero.
28: More electropositive elements have
a) Positive reduction potential
b) Negative reduction potential
c) Tendency to gain electrons
d) Negative oxidation potential
29: When a copper wire is placed in a solution of AgNO3 the solution acquires blue color. This is due to the formation of
a) Cu2+ ions.
b) Cu+ ions.
c) A soluble complex of Cu with AgNO3
d) Cu2+ ions due to reduction of Cu.
30: In a cell containing zinc electrode and standard hydrogen electrode, the zinc electrode acts as
c) A reduction center.
d) None of these.
31: Which of the following solutions will conduct electricity quite well?
d) Pure water
32: Stronger the oxidizing greater is the
a) Reduction potential
c) Oxidation potential.
d) None of these
33: The correct order of chemical reactivity with water according to electrochemical series is
34: The oxidation number of v in Cs4Na(HV10O28) is
35: SHE can be used as..
a) Only anode
b) Only cathode
c) Both anode and cathode
d) Neither anode nor cathode
36: Oxidation numbers of in H2C04, CH4 and diamond respectively are
a) +3, 4 and +4
b) +6, -4 and, zero
c) +3, – 4 and zero
d) +6, +4 and +4
37: In an aqueous solution, hydrogen will not reduce
38: Which of the following is strongest reducing agent?
39: In the reaction
4Fe + + 302 —> 4Fe3+ + 602-
Which of the following statements is incorrect?
a) Metallic iron is reducing agent
b) Metallic iron is reduced to Fe3+
c) Fe3+ is an oxidizing agent
d) Redox reaction
40: A standard hydrogen electrode has zero electrode potential because
a) Hydrogen is easiest to oxidize
b) Hydrogen atom has only one electron
c) Its electrode potential assumed to be zero
d) Hydrogen is the lightest element
41: Of the following metals, those that cannot be obtained by the electrolysis of the aqueous solution of their salts are
a) Ag and Mg
b) Ag and Al
c) Mg and Al
d) Cu and Cr
42: Which of the following metal ions will discharge first at electrode?
43: In a cell that utilizes the reaction
Zn (s) + 2H+ (aq) —> Zn2+ (aq) + H2(g)
Addition of H2SO4 to cathode compartment will
a) Increase the E and shift the equilibrium to the left
b) Lower the E and shift equilibrium to the right
c) Lower the E and shift the equilibrium to the left
d) Increase the E and shift the equilibrium to the right
44: Standard reduction electrode potentials of three metals A, B and C are +0.5V, -0.3V and -1.2V respectively. The reducing power of these metals
a) B > C > A
b) A > B > C
c) C > B > A
d) A > C > B
45: In a hydrogen-oxygen fuel cell, combustion of hydrogen occurs to
a) Produce high purity water
b) Generate heat
c) Remove adsorbed oxygen from electrode surfaces
d) Create potential difference between the two electrodes
46: The standard reduction potentials of Cu2+/Cu and Cu2+/Cu+ are 0.337 V and 0.153 V respectively. The standard electrode potential of Cu+ /Cu cell is
a) 0.184 V
b) 0.827 V
47: A dilute aqueous solution of Na2SO4 is electrolyzed using platinum electrodes, products at the anode and cathode are
a) 02, H2
b) S2082+, Na
c) 02, Na
d) S2082+, H2
48: the metal which can be displaced by all other metals from its salt solution?
49: When aluminum is coupled with Copper electrode in a galvanic cell
a) Reduction takes place at aluminum electrode
b) Oxidation takes place at copper electrode
c) Reduction at copper electrode
d) Aluminum deposits
50: The oxidation state of chromium is different in which of the following
51: Salt bridge is used in galvanic cells to:
a) Reduce the electrical resistance in the cell
b) Complete the circuit
c) Separate cathodic solution to anodic solution
d) Carry salts for chemical reactions to occur in the cell
52: Of the following aqueous solutions conduct an electric current quite well?
b) Pure water
53: Molten NaCl conducts electricity due to the presence of:
a) Free ions
b) Free electron
c) Free molecules
d) Atoms of & chloride
54: Which one of the following statements is incorrect?
a) Oxidation always takes place at anode
b) The standard reduction potentials are always taken as negative
c) Oxidation potential and reduction potential of an electrode are equal in magnitude
d) Anode contain -ve charge in galvanic cell
55. If reaction A + e- à A– has a large negative reduction potential. It follows that
a) A is Oxidizing agent
b) A– is readily reduced
c) A is readily oxidized
d) A– is readily oxidized
56: Salt bridge transfers
57: Greater value of standard reduction smaller will be tendency
a) To form positive ions
b) To form negative ions
c) To gain electrons
d) All are possible
58: In which of the following Sulfur Shows +4 oxidation state
59: The cathodic reaction in electrolysis of dilute Sulphuric acid with platinum is:
c) Both oxidation & reduction
60: During electrolysis electrons are:
c) Gained by cations & lost by anions
d) Lost by cations & gained by anions