CBSE Questions for Class 12 Engineering Chemistry Electrochemistry Quiz 2 - MCQExams.com

What is the cell reaction occurring in Daniell cell (galvanic cell)?
  • $$Cu(s) + ZnSO_{4}(aq.) \rightarrow CuSO_{4}(aq.) + Zn(s)$$
  • $$Zn(s) + CuSO_{4}(aq.) \rightarrow Cu(s) + ZnSO_{4}(aq.)$$
  • $$Ni(s) + ZnSO_{4}(aq.) \rightarrow NiSO_{4}(aq.) + Zn(s)$$
  • $$2Na(s) + CdSO_{4}(aq.) \rightarrow Na_{2}SO_{4}(aq.) + Cd(s)$$
On passing one faraday of electricity through a dilute solution of an acid, the volume of hydrogen obtained at NTP is__________.
  • $$22400\ mL$$
  • $$1120\ mL$$
  • $$2240\ mL$$
  • $$11200\ mL$$
The number of electrons involved when one faraday of electricity is passed through an electrolytic solution is:
  • $$96500$$
  • $$8\times 10^{6}$$
  • $$12\times 10^{16}$$
  • $$6\times 10^{23}$$
Substance which give good conducting aqueous solution are called:
  • weak electrolytes
  • strong electrolytes
  • non-electrolytes
  • catalysts
When one Faraday current is passed, which of the following would deposit $$1 g$$ atomic weight of the metal?
  • $$NaCl$$
  • $$Ba{Cl}_{2}$$
  • $$Al{Cl}_{3}$$
  • $$CuS{O}_{4}$$
Which is not true for electrolysis:
  • Electrolysis is used for depositing thin layer of one metal on other
  • Electrolysis is used for manufacturing some gases and compounds
  • Electrolysis can be used for refining of metals
  • Electrolysis can be used for electro plating of metals like gold & silver on other metals
When an aqueous solution of $$AgNO_3$$ is electrolysed between platinum electrodes, the substances liberated at anode and cathode are:
  • Silver is deposited at cathode and $$O_2$$ is liberated at anode
  • Silver is deposited at cathode and $$H_2$$ is liberated at anode
  • Hydrogen is liberated at cathode and $$O_2$$ is liberated at anode
  • Silver is deposited at cathode and Pt is dissolved in electrolyte
Consider the given circuit carefully, What do you think would happen if the two copper plates are moved further apart from each other ?
613855_fcf21a7923784ba181a7a6a1d3d033c0.png
  • Larger amount of copper will be deposited on the plate connected to the negative electrode
  • Smaller amount of copper will be deposited on the plate connected to the negative electrode
  • Larger amount of copper will be deposited on the plate connected to the positive electrode
  • Smaller amount of copper will be deposited on the plate connected to the positive electrode
$$Zn(s)|ZnCl_2(aq)|  |Cl^-(aq)|Cl_2(g)|C(s)$$
In the electrochemical cell described by the cell diagram above, what reaction occurs at the anode?
  • $$Zn \rightarrow Zn^{2+}+2e^-$$
  • $$Zn^{2+}+2e^- \rightarrow Zn$$
  • $$Cl_2 + 2e^-\rightarrow 2Cl^-$$
  • $$2Cl^- \rightarrow Cl_2 +2e^-$$
Statement 1: In an electrochemical cell, the electrode that is the site of reduction is called the anode.
Statement 2: Oxidation always occurs at the cathode. 
  • Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation of Statement 1.
  • Both the Statement 1 and Statement 2 are correct, but Statement 2 is NOT the correct explanation of Statement 1.
  • Statement 1 is correct, but Statement 2 is not correct.
  • Both the Statement 1 and Statement 2 are not correct.
Which one of the following conditions will increase the voltage of the cell represented by the equation?
$$Cu(s) + 2Ag^{+}(aq.) \rightleftharpoons Cu^{2+}(aq.) + 2Ag(s)$$.
  • Increase in the dimension of $$Cu$$ electrode
  • Increase in the dimension of $$Ag$$ electrode
  • Increase in the concentration of $$Cu^{2+}$$ ion
  • Increase in the concentration of $$Ag^{+}$$ ion
When lead accumulator is charged, it is:
  • an electrolytic cell
  • a galvanic cell
  • a daniell cell
  • None of these
One faraday of electricity will liberate one gram mole of the metal from the solution of:
  • $$BaCl_{2}$$
  • $$CuSO_{4}$$
  • $$AlCl_{3}$$
  • $$NaCl$$
Among $$Na, Hg, S, Pt$$ and graphite, which can be used as electrodes in electrolytic cells having aqueous solutions?
  • $$Hg$$ and $$Pt$$
  • $$Hg, Pt$$ and graphite
  • $$Na$$ and $$S$$
  • $$Na, Hg$$ and $$S$$
On heating, sodium and sulphur can be melted. Molten sodium and molten sulphur are used ?
  • For refining lead
  • As a medium for extracting metals
  • As catalysts
  • As electrodes in a modern kind of battery
Chromium metal can be plated out from an acidic solution containing $$CrO_3$$ according to the following equation $$CrO_3(aq)+6H^+(aq)+6e^-\rightarrow Cr(s)+3H_2O$$
Calculate how many grams of chromium will be placed out by $$24000$$ coulombs (Atomic Weight of Cr$$=52$$).
  • $$2.15$$ gram
  • $$0.36$$ gram
  • $$21.5$$ gram
  • None
  • Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
  • Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
  • Assertion is correct but Reason is incorrect
  • Both Assertion and Reason are incorrect
Selenium has the unusual property of being a good conductor in light but a poor conductor in the dark. It was, therefore, used in making.
  • Shaded glass
  • Photo-electric cells
  • Photo chemical celles
  • Chromatic lenses
Kunal took few iron turnings and mixed them well with Sulphur powder. He could separate the iron turnings with the help of a magnet. He heated the mixture for some time and tried to separate the iron turnings with the magnet but he could not. Why?
  • On heating, a chemical change takes place and a new compound is formed.
  • On heating, iron becomes non-magnetic hence, it is not attracted by magnet.
  • On heating, a physical change takes place hence iron and Sulphur gets mixed up.
  • On heating, iron evaporates and only sulphur is left behind
Is the reaction, $$2Al + 3Fe^{2+}\rightleftharpoons 2Al^{3+} + 2Fe$$ possible?
  • No, because standard oxidation potential of $$Al < Fe$$
  • Yes, because standard oxidation potential of $$Al > Fe$$
  • Cannot be predicted
  • Yes, because aluminium is a strong oxidising agent
Which molecule electrolysis temperature is maximum?
  • $$As{H}_{3}$$
  • $${NH}_{3}$$
  • $${PH}_{3}$$
  • $$Sb{H}_{3}$$
The charge which is not possible, is:
  • $$-1.6\times 10^{-19}C$$
  • $$-3.2\times 10^{-20}C$$
  • $$-4.8\times 10^{-19}C$$
  • $$-3.2\times 10^{-18}C$$
$$10800\ C$$ of electricity through the electrolyte deposited $$2.977\ g$$ of metal with atmic mass $$106.4\ g\ mol^{-1}$$. The charge on the metal cation is:
  • $$+4$$
  • $$+3$$
  • $$+2$$
  • $$+1$$
The mass ratio of Al and Ag deposited using the same quantity of current is:
  • $$9:108$$
  • $$2:12$$
  • $$108:9$$
  • $$3:8$$
Negative terminal of a dry cell is formed by:
  • zinc container
  • carbon rod
  • graphite rod
  • both A and B
A Voltaic cell consists of an electrode of solid silver immersed in 0.10M $${ AgNO }_{ 3 }$$ Solution and an electrode of unknown metal X immersed in a 0.10M solution $${ X(NO }_{ 3 })_{ 2 }$$. A porous barrier separates the two half of the cell. Also given:

$$E\left( { Ag^{ + } }/{ Ag } \right)$$ = 0.80V and $${ E }_{ cell }$$ = 1.05V and at 25 degree Celsius

$${ X_{ (s) } }/{ { X }^{ 2+ } }(1.0M)\parallel { Ag }^{ + }(0.1M)/{ Ag }_{ (s) }$$

Which of the following statements regarding the cell and X is correct?
  •  Standard Emf (E) of $${ { X }^{ 2+ } }/{ X }$$ is -0.25V at 25 degree Celsius
  • X is a stronger reducing agent than $${ H }_{ 2{ (g) } }$$
  •  As cell operate, concentrations of both $${ X }^{ 2+ }and{ Ag }^{ + }$$ increases in their respective half cells
  •  As cell operate, concentration of $${ X }^{ 2+ }$$ increases in anode chamber while concentration of $${ Ag }^{ + }$$ decreases in cathode chamber
By which of the following change, it is possible to increases the voltage of a cell in which in the reaction is:
$$Cu^{2+} (aq)+ Zn(s) \rightarrow Cu(s)+ Zn^{2+}(aq)$$
  • by increasing the concentration of zinc ion
  • by increasing the concentration of copper ion
  • by changing the size of zinc electrode
  • by increasing the size of copper electrode.
For a cell reaction represented by the equation $$Cu(s)+2Ag^{+}(aq)\rightarrow Cu^{2+}(aq)+2Ag(s)$$ the value of $$\Delta G^{\circ}$$ could be obtained by 
  • setting up $$Cu(s)/Cu^{2+}(aq)$$ and $$Ag(s)/Ag^{+}(aq)$$ half - cells (using molar solution and measuring the emf of the resulting cell)
  • adding powered copper to a solution of $$Ag^{+}$$ ions and determining the enthalpy cgange, repeating this experiment at different temperatures
  • Setting up $$Cu(s)/Cu^{2+}(aq)$$ and $$Ag(s)/Ag^{+}(aq)$$ half-cells and determining the molarities of the ions which gives an emf of zero for the cell
  • Setting up $$Cu(s)/Cu^{2+}(aq)$$ and $$Ag(s)/Ag^{+}(aq)$$ half-cells, using the resultant emf to drive a motor and measuring the work which it can do
One gm metal $${ M }^{ 3+ }$$ was discharged by the passage of $$1.81$$ $$\times $$ $${10}^{23}$$ electrons. What is the atomic weight of metal ?
  • $$ 33.35$$
  • $$ 133.4$$
  • $$ 66.7$$
  • None of these
Without losing its concentration $$ZnCl_2$$ solution cannot be kept in contact with :
  • $$Au$$
  • $$Al$$
  • $$Pb$$
  • $$Ag$$
State whether the following statements are True of False:
In galvanic (voltaic) cell, the positive electrode is called cathode and the negative electrode is called anode.
  • True
  • False
A dry cell converts chemical energy into:
  • mechanical energy
  • heat energy
  • electrical energy
  • light energy

In an electrolytic cell cathode acts as:
  • an oxidizing agent
  • reducing agent
  • either of the two
  • neither of the two
On the basis of the following $$E^0$$ the strongest oxidising agent is:
$$\begin{array}{l}{\left[ {Fe{{\left( {CN} \right)}_6}} \right]^{4 - }} \to {\left[ {Fe{{\left( {CN} \right)}_6}} \right]^{3 - }} + {e^ - };{E^0} =  - 0.35V\\F{e^{2 + }} \to F{e^{3 + }} + {e^ - };{E^0} =  - 0.77V\end{array}$$ 
  • $$F{e^{3 + }}$$
  • $${\left[ {Fe{{\left( {CN} \right)}_6}} \right]^{3 - }}$$
  • $${\left[ {Fe{{\left( {CN} \right)}_6}} \right]^{4 - }}$$
  • $$F{e^{2 + }}$$
A galvanic cell is made up of two hydrogen electrodes one of which is a standard one. In which of the following solutions should the other electrode be immersed to get maximum emf ?
  • $$0.01\quad M-HCOOH$$
  • $$0.1\quad M-HCl$$
  • $$0.1\quad M-{ H }_{ 2 }{ SO }_{ 4 }$$
  • $$0.1\quad M-{ NH }_{ 4 }OH$$
In the galvanic cell, $$Ca|{ Ca }^{ 2+ }(1M)\parallel { Ag }^{ + }(1M)|Ag$$, the electrons will travel in the external circuit:
  • From $$Ag$$ to $$Ca$$
  • From $$Ca$$ to $$Ag$$
  • Electrons do not travel in the external circuit
  • In any direction
 
1167524_f8427b27d04c4e6f8d9f230cf05a188d.JPG
  • $$2\times$$$$10^{-2}$$ $$M$$
  • $$2\times$$$$10^{-3}$$ $$M$$
  • $$1.5\times$$$$10^{-3}$$ $$M$$
  • $$1.5\times$$$$10^{-2}$$ $$M$$
In the cell, $$Zn|Zn^{2+}||Cu^{2+}|Cu,$$ the negative electrode is 
  • $$Cu$$
  • $$Cu^{2+}$$
  • $$Zn$$
  • $$Zn^{2+}$$
An amino acid migrates towards the cathode when the electric field is applied. This implies that 
  • pH> pl
  • Pl >pH
  • Pl=pH
  • None of these
How many coulombs of electricity are required for the oxidation of  $$1$$ mole of  $$\mathrm { H } _ { 2 } \mathrm { O }$$  to  $$\mathrm { O } _ { 2 }$$ ?
  • $$9.65 \times 10 ^ { 4 } C$$
  • $$4.825 \times 10 ^ { 5 } \mathrm { C }$$
  • $$1.93 \times 10 ^ { 5 } C$$
  • $$1.93 \times 10 ^ { 4 } C$$

In hydrogen evolution type of corrosion with respect to hydrogen electrode which of the following is correct ?
  • the metal with more negative SRP value under the given conditions
  • the metal with more positive SRP value under the given conditions
  • the metal with both negative and positive SRP values
  • All the above

The factors that promote electro chemical corrosion are _____________.
  • the nature of the impurity metal with which the metal under consideration is associated.
  • the concentration of $$O_{2}$$ in contact with the surface of the metal.
  • highly conducting solutions.
  • all the above.
Consider the following $$\;{{\text{E}}^{\text{o}}}\;$$ values,
$${{\text{E}}^{\text{o}}}_{{\text{F}}{{\text{e}}^{{\text{3 + }}}}{\text{/F}}{{\text{e}}^{{\text{2 + }}}}} = {\text{ + 0}}{\text{.77V}};$$$${{\text{E}}^{\text{o}}}_{{\text{S}}{{\text{n}}^{{\text{2 + }}}}{\text{/Sn}}} =  - {\text{0}}{\text{.14V}}\;\;\;\;$$

Under standard conditions the potential for the reaction is:
$${\text{Sn}}\left( {\text{s}} \right){\text{ + 2F}}{{\text{e}}^{{\text{3 + }}}}\left( {{\text{aq}}} \right) \to {\text{2F}}{{\text{e}}^{{\text{2 + }}}}{\text{(aq) + S}}{{\text{n}}^{{\text{2 + }}}}\left( {{\text{aq}}} \right)$$
  • 0.91 V
  • 1.40 V
  • 1.68 V
  • 0.63 V

Corrosion is a/an:
  • physical change
  • neutralisation reaction
  • electrochemical change
  • none of the above

In electro-chemical corrosion of metals, the metal undergoing corrosion:
  • Becomes anode
  • Becomes cathode
  • Becomes inert
  • None is correct

An iron rod is immersed in $$KCl$$ solution such that half its length is exposed to air and the other half immersed in $$KCl$$ solution. The part corroded faster is __________.
  • part of the rod exposed to air
  • part of the rod immersed in $$KCl$$ solution
  • both A & B
  • none of the above
Number of coulombs required to deposit $$90\ g$$ of $$Al$$ when the electrode reaction $$Al^{3+}+3e\rightarrow Al$$ is
  • $$9.65\ \times 10^{6}$$
  • $$8.685\ \times 10^{4}$$
  • $$9.65\ \times 10^{4}$$
  • $$6.955$$
Three faradays of electricity is passed through molten solutions of $$Ag{NO}_{3}, Ni{SO}_{4}$$ and $$Cr{Cl}_{3}$$ kept in three vessels using inert electrodes. The ratio in mol in which the metals $$Ag, Ni$$ and $$Cr$$ will be deposited is:
  • $$1:2:3$$
  • $$3:2:1$$
  • $$6:3:2$$
  • $$2:3:6$$
Corrosion can be an advantage in which of the following cases?
  •  A layer of oxide is formed on surface, which protects the inner metal from corrosion
  • During the rusting of iron
  • The Hulls of the boat in the sea getting rusted due to salt water
  • None of the above
The cell for which the cell reaction is $$ H_2+Cu^{2+} \rightarrow 2H^++Cu $$ is represented as:
  • $$ Cu|Cu^{2+} || H^+| H_2 $$
  • $$ H_2(g) | H^+ ||Cu^{2+} |Cu $$
  • $$ Pt;H_2(1atm), H^+||Cu^{2+}|Cu $$
  • $$ Pt;H_2|H^+ (aq) (1atm),||Cu^{2+}|Cu $$
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