Electrochemistry Test 3

Total Questions:50 Total Time: 75 Min



Questions 1 of 50

Question:When lead storage battery is charged

Answers Choices:

Lead dioxide dissolves

Sulphuric acid is regenerated

The lead electrode becomes coated with lead sulphate

The amount of sulphuric acid decreases

Questions 2 of 50

Question:The electrolytic decomposition of dilute sulphonic acid with platinum electrode in cathodic reaction is

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Oxidation and reduction both


Questions 3 of 50

Question:The specific conductance of a solution is 0.2 \(oh{m^{ - 1}}c{m^{ - 1}}\)and conductivity is 0.04 \(oh{m^{ - 1}}\). The cell constant would be

Answers Choices:

1 \(c{m^{ - 1}}\)

0 \(c{m^{ - 1}}\)

5 \(c{m^{ - 1}}\)

0.2 \(c{m^{ - 1}}\)

Questions 4 of 50

Question:If the conductance and specific conductance of a solution is one then its cell constant would be

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Questions 5 of 50

Question:In electroplating, the article to be electroplated serves as

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Questions 6 of 50

Question:The position of some metals in the electrochemical series in decreasing electropositive character is given as \(Mg > Al > Zn > Cu > Ag.\) What will happen, if a copper spoon is used to stir a solution of aluminium nitrate

Answers Choices:

The spoon will get coated with \(Al\)

An alloy of \(Cu\) and \(Al\) is formed

The solution becomes blue

There is no reaction

Questions 7 of 50

Question:The chemical reaction, \(2AgCl(s) + {H_2}(g)\; \to \) \(2HCl(aq) + 2Ag(s)\) taking place in a galvanic cell is represented by the notation

Answers Choices:


\(Pt(s)|{H_2}(g),\;1{\rm{bar|}}\;1M\;HCl(aq)||1M\;A{g^ + }(aq)|Ag(s)\)



Questions 8 of 50

Question:If the \(Z{n^{2 + }}/Zn\) electrode is diluted to 100 times then the change in e.m.f.

Answers Choices:

Increase of \(59\,mV\)

Decrease of \(59\,mV\)

Increase of \(29.5\,mV\)

Decrease of \(29.5\,mV\)

Questions 9 of 50

Question:Which of the following shows electrical conduction

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Questions 10 of 50

Question:The unit of equivalent conductivity is

Answers Choices:

ohm cm

\(oh{m^{ - 1}}c{m^2}\,{(gm\,\;equivalent)^{ - 1}}\)

ohm \(c{m^2}\,(gm\,\,equivalent)\)

\(S\,c{m^{ - 2}}\)

Questions 11 of 50

Question:Corrosion is basically a

Answers Choices:

Altered reaction in presence of \({H_2}O\)

Electrochemical phenomenon


Union between light metal and heavy metal

Questions 12 of 50

Question:Rusting of iron is catalysed by which of the following

Answers Choices:




\({H^ + }\)

Questions 13 of 50

Question:When a copper wire is placed in a solution of \(AgN{O_3}\), the solution acquires blue colour. This is due to the formation of

Answers Choices:

\(C{u^{2 + }}\) ions

\(C{u^ + }\) ions

Soluble complex of copper with \(AgN{O_3}\)

\(C{u^ - }\) ion by the reduction of \(Cu\)

Questions 14 of 50

Question:Consider the reaction \(M_{(aq)}^{n + } + n{e^ - } \to {M_{(s)}}\). The standard reduction potential values of the elements \({M_1},\,{M_2}\) and \({M_3}\) are \( - 0.34V,\, - \,3.05\,V\) and \( - 1.66\,V\) respectively. The order of their reducing power will be

Answers Choices:

\({M_1} > {M_2} > {M_3}\)

\({M_3} > {M_2} > {M_1}\)

\({M_1} > {M_3} > {M_2}\)

\({M_2} > {M_3} > {M_1}\)

Questions 15 of 50

Question:The standard electrode potential for the two electrode \({A^ + }/A\) and \({B^ + }/B\) are respectively 0.5 \(V\) and 0.75 \(V\). The \(emf\) of the given cell \(A\,\,|\,\,{A^ + }(a = 1)\,\,||\,\,{B^ + }(a = 1)\,\,|\,\,B\) will be

Answers Choices:

1.25 \(V\)

-1.25 \(V\)

-0.25 \(V\)

0.25 \(V\)

Questions 16 of 50

Question:The standard reduction potential for \(L{i^ + }/Li\,;\,\,Z{n^{2 + }}/Zn\,;\) \({H^ + }/{H_2}\) and \(A{g^ + }/Ag\) is \( - 3.05,\,\, - 0.762,\,\,0.00\) and \( + 0.80\,\,V.\) Which of the following has highest reducing capacity

Answers Choices:





Questions 17 of 50

Question:A standard hydrogen electrode has zero electrode potential because

Answers Choices:

Hydrogen is easiest to oxidize

The electrode potential is assumed to be zero

Hydrogen atom has only one electron

Hydrogen is the lightest element

In the electrochemical cell

Questions 18 of 50

Question:\({H_2}(g)\,1\,atm\,|{H^ + }(1M)||C{u^{2 + }}(1M)\,|Cu(s)\). Which one of the following statements is true

Answers Choices:

\({H_2}\) is cathode; \(Cu\) is anode

Oxidation occurs at \(Cu\) electrode

Reduction occurs at \({H_2}\) electrode

\({H_2}\) is anode; \(Cu\) is cathode

Questions 19 of 50

Question:\({E^o}\) for the cell \(Zn|Z{n^{2 + }}(aq)||C{u^{2 + }}(aq)|Cu\) is \(1.10\,V\) at \({25^o}C\), the equilibrium constant for the reaction \(Zn + C{u^{2 + }}(aq)\)?\(Cu + Z{n^{2 + }}(aq)\) is of the order of

Answers Choices:

\({10^{ - 28}}\)

\({10^{ - 37}}\)

\({10^{ + 18}}\)

\({10^{ + 17}}\)

Questions 20 of 50

Question:Standard reduction potentials at \({25^o}C\) of \(L{i^ + }|Li,\,B{a^{2 + }}|\,Ba,\,N{a^ + }|\,Na\) and \(M{g^{2 + }}|Mg\) are \( - 3.05,\, - 2.90,\, - 2.71\) and \( - 2.37\) volt respectively. Which one of the following is the strongest oxidising agent

Answers Choices:

\(N{a^ + }\)

\(L{i^ + }\)

\(B{a^{2 + }}\)

\(M{g^{2 + }}\)

Questions 21 of 50

Question:For the electrochemical cell, \(M|{M^ + }||{X^ - }|X,\)\({E^o}({M^ + }/M)\) = 0.44 V and \({E^o}(X/{X^ - })\)= 0.33 V. From this data one can deduce that

Answers Choices:

\(M\, + \,X\, \to {M^ + } + {X^ - }\) is the spontaneous reaction

\({M^ + } + {X^ - } \to M + X\) is the spontaneous reaction

\({E_{cell}}\)= 0.77 V

\({E_{cell}}\)= – 0.77 V

Questions 22 of 50

Question:The standard potential at \({25^o}C\) for the following half reactions are given against them \(Z{n^{2 + }} + 2e \to Zn,{E^o} = - 0.762V\)\(M{g^{2 + }} + 2e \to Mg,{E^o} = - 2.37V\)When zinc dust is added to the solution of \(MgC{l_2}\)

Answers Choices:

\(ZnC{l_2}\)is formed

Zinc dissolves in the solution

No reaction takes place

\(Mg\)is precipitated

Questions 23 of 50

Question:Zinc displaces copper from the solution of its salt because

Answers Choices:

Atomic number of zinc is more than that of copper

Zinc salt is more soluble in water than the copper salt

Gibbs free energy of zinc is less than that of copper

Zinc is placed higher than copper in electro-chemical series

Questions 24 of 50

Question:An electrochemical cell is set up as follows \(Pt({H_2},\,1\,atm)/0.1\,M\,HCl\) || 0.1 M acetic acid /( \({H_2},\,1\,atm\)) Pt E.M.F. of this cell will not be zero because

Answers Choices:

The \(pH\) of 0.1 M HCl and 0.1 M acetic acid is not the same

Acids used in two compartments are different

E.M.F. of a cell depends on the molarities of acids used

The temperature is constant

Questions 25 of 50

Question:For the electrochemical cell, \(M|{M^ + }||{X^ - }|X,\) \(E^\circ ({M^ + }|M)\)\( = 0.44\;V\)\(E^\circ (X|{X^ - }) = 0.33\;V\)From this data, one can deduce that

Answers Choices:

\(E{^\circ _{cell}} = - 0.77\,V\)

\({M^ + } + {X^ - } \to M + X\) is the spontaneous reaction

\(M + X \to {M^ + } + {X^ - }\)is the spontaneous reaction

\(E{^\circ _{cell}} = .77\;V\)

Questions 26 of 50

Question:The standard e.m.f. of a call, involving one electron change is found to be \(0.591\;V\) at 25°C. The equilibrium constant of the reaction is (\(F = 96,500\;C\;mo{l^{ - 1}};\) \(R = 8.314\;J{K^{ - 1}}mo{l^{ - 1}})\)

Answers Choices:

\(1.0 \times {10^{10}}\)

\(1.0 \times {10^5}\)

\(1.0 \times {10^1}\)

\(1.0 \times {10^{30}}\)

Questions 27 of 50

Question:Standard electrode potential of cell \({H_2}|{H^ + }||A{g^ + }|Ag\) is

Answers Choices:

0.8 V

0.8 V

1.2 V

1.2 V

Questions 28 of 50

Question:The standard electrode potential is measured by

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Questions 29 of 50

Question:Aluminium displaces hydrogen from acids but copper does not. A galvanic cell prepared by combining \(Cu/C{u^{2 + }}\)and \(Al/A{l^{3 + }}\)has an e.m.f. of 2.0 V at 298 K. If the potential of copper electrode is + 0.34 V, that of aluminium is

Answers Choices:

+ 1.66 V

1.66 V

+ 2.34 V

2.3 V

Questions 30 of 50

Question:If the standard electrode potential of \(C{u^{2 + }}/Cu\) electrode is 0.34V, what is the electrode potential of 0.01M concentration of \(C{u^{2 + }}\) \((T = 298\,K)\)

Answers Choices:

0.399 V

0.281 V

0.222 V

0.176 V

Questions 31 of 50

Question:Which of the following compounds will not undergo decomposition on passing electricity through aqueous solution

Answers Choices:


Sodium Chloride

Sodium Bromide

Sodium Acetate

Questions 32 of 50

Question:During the electrolysis of an electrolyte, the number of ions produced, is directly proportional to the

Answers Choices:

Time consumed

Electro chemical equivalent of electrolysis

Quantity of electricity passed

Mass of electrons

Questions 33 of 50

Question:In the electrolytic cell, flow of electrons is from

Answers Choices:

Cathode to anode in solution

Cathode to anode through external supply

Cathode to anode through internal supply

Anode to cathode through internal supply

Questions 34 of 50

Question:In electrolysis of aqueous copper sulphate, the gas at anode and cathode is

Answers Choices:

\({O_2}\) and \({H_2}\)

\(S{O_2}\) and \({H_2}\)

\({H_2}\) and \({O_2}\)

\(S{O_3}\) and \({O_2}\)

Questions 35 of 50

Question:Use of electrolysis is

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1 and 2 both

None of these

Questions 36 of 50

Question:Sodium is made by the electrolysis of a molten mixture of about 40% \(NaCl\) and 60% \(CaC{l_2}\) because

Answers Choices:

\(CaC{l_2}\) helps in conduction of electricity

This mixture has a lower melting point than \(NaCl\)

\(C{a^{ + + }}\) can displace \(Na\) from \(NaCl\)

\(C{a^{ + + }}\) can reduce \(NaCl\) to \(Na\)

Questions 37 of 50

Question:Three faradays electricity was passed through an aqueous solution of iron (II) bromide. The weight of iron metal (at. wt. = 56) deposited at the cathode (in gm) is

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Questions 38 of 50

Question:A silver cup is plated with silver by passing 965 coulombs of electricity, the amount of silver deposited is

Answers Choices:

9.89 g

107.87 g

1.0787 g

1.002 g

Questions 39 of 50

Question:The atomic weight of \(Al\) is 27. When a current of 5 Faradays is passed through a solution of \(A{l^{ + + + }}\)ions, the weight of \(Al\) deposited is

Answers Choices:

27 gm

36 gm

45 gm

39 gm

Questions 40 of 50

Question:When 1 coulomb of charge is passed through electrolyte solution, then the mass deposited is equal to

Answers Choices:

Equivalent weight

Atomic weight

Electrochemical equivalent

Chemical equivalent

Questions 41 of 50

Question:The platinum electrodes were immersed in a solution of cupric sulphate and electric current passed through the solution. After some time it was found that colour of copper sulphate disappeared with evolution of gas at the electrode. The colourless solution contains

Answers Choices:

Platinum sulphate

Copper hydroxide

Copper sulphate

Sulphuric acid

Questions 42 of 50

Question:On passing \(C\) ampere of electricity through a electrolyte solution for \(t\) second, \(m\)gram metal deposits on cathode. The equivalent weight \(E\) of the metal is

Answers Choices:

\(E = \frac{{C \times t}}{{m \times 96500}}\)

\(E = \frac{{C \times m}}{{t \times 96500}}\)

\(E = \frac{{96500 \times m}}{{C \times t}}\)

\(E = \frac{{C \times t \times 96500}}{m}\)

Questions 43 of 50

Question:In a metal oxide, there is 20% oxygen by weight. Its equivalent weight is

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Questions 44 of 50

Question:On the basis of the information available from the reaction \(\frac{4}{3}Al + {O_2} \to \frac{2}{3}A{l_2}{O_3},\Delta G = - 827kJmo{l^{ - 1}}\) of \({O_2}\), the minimum emf required to carry out an electrolysis of \(A{l_2}{O_3}\) is (F = 96500C \(mo{l^{ - 1}}\))

Answers Choices:

8.56 V

2.14 V

4.28 V

6.42 V

Questions 45 of 50

Question:The required charge for one equivalent weight of silver deposite on cathode is

Answers Choices:

\(9.65 \times {10^7}C\)

\(9.65 \times {10^4}C\)

\(9.65 \times {10^3}C\)

\(9.65 \times {10^5}C\)

Questions 46 of 50

Question:96500 coulombs of electric current liberates from \(CuS{O_4}\) solution

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Questions 47 of 50

Question:On electrolysis, 1 mole of aluminium will be deposited from its molten salt by

Answers Choices:

3 moles of electrons

4 moles of electrons

2 moles of electrons

1 mole of electrons

Questions 48 of 50

Question:The atomic weight of \(Fe\) is 56. The weight of Fe deposited from \(FeC{l_3}\)solution by passing 0.6 Faraday of electricity is

Answers Choices:

5.6 g

11.2 g

22.4 g

33.6 g

Questions 49 of 50

Question:In the electrolysis of water, one Faraday of electrical energy would evolve

Answers Choices:

One mole of oxygen

One g atom of oxygen

8 g of oxygen

22.4 litres of oxygen

Questions 50 of 50

Question:In a galvanic cell, the electrons flow from

Answers Choices:

Anode to cathode through the solution

Cathode to anode through the solution

Anode to cathode through the external circuit

Cathode to anode through the external circuit