CBSE Questions for Class 12 Engineering Chemistry Electrochemistry Quiz 14 - MCQExams.com

The electrolysis of a solution resulted in the formation of $$H_{2}(g)$$ at the cathode and $$O_{2}(g)$$ at the anode. The solution is :
  • $$AgCl(aq)$$
  • highly concentrated $$H_{2}SO_{4}(aq)$$
  • highly concentrated $$HCl$$ solution
  • $$CuCl_{2}(aq)$$
An electric current is passed through a copper voltameter and a water voltameter connected in series. If the copper of the copper voltameter now weights 16 mg less, hydrogen liberated at the cathode of the water voltameter measures at STP about:
  • $$4.0ml$$
  • $$5.6ml$$
  • $$6.4ml$$
  • $$8.4ml$$
Coulomb is equal to ........
  • ampere $$\times$$ second
  • ampere $$\times$$ minute
  • watt $$\times$$ second
  • volt $$\times$$ second
The current strength of $$3.863\ amp$$ was passed through molten calcium oxide for $$41$$ minutes and $$40$$ seconds. The mass of calcium in grams deposited at the cathode is: (Atomic mass of Ca is $$40\ g/mol, 1\ f=96500\ C)$$
  • $$4$$
  • $$2$$
  • $$6$$
  • $$8$$
  • $$1$$
Consider the half-cell reaction(s)
$${Cu}^{2+}+{e}^{-}\rightarrow {Cu}^{+};{E}^{o}=0.15V$$
$${Cu}^{2+}+2{e}^{-}\rightarrow {Cu};{E}^{o}=0.33V$$
$${E}^{o}$$ for the half-cell reaction: $${Cu}^{+}+{e}^{-}\rightarrow Cu$$ will be:
  • $$0.48V$$
  • $$0.18V$$
  • $$0.31V$$
  • $$0.51V$$
Standard electrode potential data are useful for understanding the suitability of an oxidant in a redox titration. Some half-cell reactions and their standard potentials are given below:

$$MnO_{4}^{-}(aq)+8H^{+}(aq)+5e^{-}\rightarrow Mn^{2+}(aq)+4H_{2}O(l);$$     $$E^{\circ}= 1.51V$$
$$Cr_{2}O_{7}^{2-}(aq)+14H^{+}(aq)+6e^{-}\rightarrow 2Cr^{3+}(aq)+7H_{2}O(l);$$     $$E^{\circ}= 1.38V$$
$$Fe^{3+}(aq)+e^{-}\rightarrow Fe^{2+}(aq);$$     $$E^{\circ}= 0.77V$$
$$Cl_{2}(g)+2e^{-}\rightarrow 2Cl^{-}(aq);$$      $$E^{\circ}= 1.40V$$

Identify the only incorrect statement regarding the quantitative estimation of aqueous $$Fe(NO_{3})_{2}$$
  • $$MnO_{4}^{-}$$ can be used in aqueous $$HCl$$
  • $$Cr_{2}O_{7}^{2-}$$ can be used in aqueous $$HCl$$
  • $$MnO_{4}^{-}$$ can be used in aqueous $$H_{2}SO_{4}$$
  • $$Cr_{2}O_{7}^{2-}$$ can be used in aqueous $$H_{2}SO_{4}$$
If one mole electrons is passed through the solutions of $$AlCl_{3}, AgNO_{3}$$ and $$MgSO_{4}$$, in what ratio $$Al, Ag$$ and $$Mg$$ will be deposited at the electrodes?
  • $$3 : 6 : 2$$
  • $$2 : 6 : 3$$
  • $$1 : 2 : 3$$
  • $$3 : 2 : 1$$
The standard reduction potential of the $$Ag^+|Ag$$ electrode at 298 K is 0.80 V. The solubility product of AgI is $$6.4 \times  10^{-17}$$ at 298 K. (2.303RT/F = 0.06). The potential of $$ I^{-} (0.04 \, M)|AgI|Ag $$ electrode at 198 K is 
  • $$ -0.088\,V $$
  • $$ +0.088\,V $$
  • $$ -0.172\,V $$
  • $$ +0.172\,V $$
Which of the following statement (s) differentiate between electrochemical cell and electrolytic cell?
  • Spontaneous or non-spontaneous nature of the chemical process.
  • Chemical reactions occurring at the electrodes.
  • Positive and negative nature of anode.
  • Dependence on Faraday's law.
Two electrochemical cells are assembled in which the following reactions occur:

$$ V^{2+}+VO^{2+}+2H^{+} \rightarrow 2V^{3+}+H_{2}O\ ;\ E_{cell}^{\circ} = 0.616\ V$$

$$ V^{3+}+Ag^{+}+H_{2}O \rightarrow VO^{2+}+Ag(s)+2H^{+}\ ;\ E_{cell}^{\circ} = 0.439\ V$$

If $$ E_{Ag^{+}|Ag}^{\circ} = 0.799\ V,$$ what is $$ E_{V^{3+}|V^{2+}}^{\circ}?$$
  • $$-0.256\ V$$
  • $$+0.256\ V$$
  • $$+1.854\ V$$
  • $$-1.854\ V$$
From the following $$E^{\circ}$$ values for the half-cells:


$$(i)\ D\rightarrow D^{2+}+2e^{-};E^{\circ}=-1.5V$$

$$(ii)\ B^{+}+e^{-}\rightarrow B;E^{\circ}=-0.5V$$

$$(iii)\ A^{3-}\rightarrow A^{2-}+e^{-};E^{\circ}=1.5V$$

$$(iv)\ C^{2+}+e^{-}\rightarrow C^{+};E^{\circ}= +0.5V$$

Which combination of two half-cells would result in a cell with the largest potential?
  • $$(i)$$ and $$(iii)$$
  • $$(i)$$ and $$(iv)$$
  • $$(iii)$$ and $$(iv)$$
  • $$(ii)$$ and $$(iv)$$
Statement $$I$$: Electrolysis of $$ CuCl_{2}(aq)$$ gives 1 mole of Cu and 1 mole of $$ Cl_{2}$$ by the passage of suitable charge.
Statement $$II$$: Equal equivalents of Cu and $$ Cl_{2}$$ are formed during the passage of same charge.
  • If both statements are CORRECT, and Statement $$II$$ is the CORRECT explanation of Statement $$I$$.
  • If both statements are CORRECT, and Statement $$II$$ is NOT the CORRECT explanation of Statement $$I$$.
  • If Statement $$I$$ is CORRECT, but Statement $$II$$ is INCORRECT.
  • If Statement $$I$$ is INCORRECT,but Statement $$II$$ is CORRECT.
Statement $$I$$: An electrochemical cell can be set up only when the redox reaction is spontaneous.
Statement $$II$$: A reaction is spontaneous if free energy change at constant temperature and pressure is negative.
  • If both statements are Correct, and Statement $$II$$ is the Correct explanation of Statement $$I$$.
  • If both statements are Correct, and Statement $$II$$ is NOT the Correct explanation of Statement $$I$$.
  • If Statement $$I$$ is Correct, but Statement $$II$$ is Incorrect.
  • If Statement $$I$$ is Incorrect, but Statement $$II$$ is Correct.
Pick up the false statement(s):
  • The net chemical change in a galvanic cell reaction is always a redox reaction.
  • In a galvanic cell made of cobalt and cadmium electrodes, the cobalt electrode acts as the anode.
  • Standard potential increases with increasing concentration of the electrolyte.
  • Calomel electrode is a reference electrode having $$0.00$$ volt potential.
Which of the following solutions have highest resistance?
  • 1N - NaCl
  • 0.05 N - NaCl
  • 2N - NaCl
  • 0.1 N - NaCl
The graph represent a current-voltage behaviour of water. Choose the correct option:
1704943_f8d1cd6910b94817b0bb6a80962f5135.png
  • Ohm's law is obeyed
  • Electrolysis in general do not obey ohm's law
  • Dissociation takes place at E, and it obeys Ohm's law thereafter
  • Ohm's law is not valid for low voltage
Which of the following statements does not differentiate between electrochemical cell and electrolytic cell?
  • Spontaneous or non-spontaneous nature of the chemical process.
  • Chemical reactions occurring at the electrodes
  • Positive and negative nature of anode.
  • EMF measurement.
Statement $$II$$: In an electrochemical cell, anode and cathode are, respectively, negative and positive electrode.
Statement $$II$$: At anode, oxidation takes place and at cathode reduction takes place.
  • If both statements are CORRECT, and Statement $$II$$ is the CORRECT explanation of Statement $$I$$.
  • If both statements are CORRECT, and Statement $$II$$ is NOT the CORRECT explanation of Statement $$I$$.
  • If Statement $$I$$ is CORRECT, but Statement $$II$$ is INCORRECT.
  • If Statement $$I$$ is INCORRECT, but Statement $$II$$ is CORRECT.
$${ E }_{ cell }^{ o }$$ for the reaction $$Co(s)+{ Ni }^{ 2+ }\quad \longrightarrow { Co }^{ 2+ }+Ni(s)$$ is $$+0.03$$ volt. If cobalt metal is added to an aqueous solution  having $$\left[ { Ni }^{ 2+ } \right] =1M$$
  • the reaction will not proceed in the forward direction at all
  • the displacement of $${Ni}^{2+}$$ from solution by $$Co$$ will go to completion
  • the displacement of $${Ni}^{2+}$$ from solution by $$Co$$ will proceed to a considerable extent, but the reaction will stop before the $${Ni}^{2+}$$ is completely displaced
  • only the reverse reaction will occur
Resistance of 0.2 M solution of an electrolyte is 50 $$\Omega $$. The specific conductance of the solution of 0.5 M solution of the same electrolyte is 1.4 S $$ m^{-1} $$ and resistance of the same solution of the electrolyte is 280 $$\Omega $$. The molar conductivity of 0.5 M solution of the electrolyte is ?
  • $$ 5\times 10^{-4} $$
  • $$ 5\times 10^{-3} $$
  • $$ 5\times 10^{3} $$
  • $$ 5\times 10^{2} $$
Corrosion is an electrochemical process. It involves:
  • Loss of electrons by iron, $$Fe\longrightarrow Fe^{2+}+2e$$. i.e iron acts as an anode
  • Impurities act as a cathode. Electrons are used in forming hydroxyl ions
    $$H_2O+O+2e \longrightarrow 2OH^-$$
  • Ferrous ions are oxidised to ferries ions in presence of dissolved oxygen.
    $$2Fe^{2+}+O+H_2O\longrightarrow 2Fe^{3+}+2OH^-$$
  • All the above reactions
$$\cfrac { 1 }{ 2 } { H }_{ 2 }(g)+AgCl(s)={ H }^{ + }(aq)+{ Cl }^{ - }(aq)+Ag(s)$$ occurs in the galvanic cell:
  • $$Ag/AgCl(s)|KCl(sol)\parallel Ag{ NO }_{ 3 }(sol)|Ag\quad $$
  • $$Pt/{ H }_{ 2 }(g)|HCl(sol)\parallel Ag{ NO }_{ 3 }(sol)|Ag$$
  • $$Pt/{ H }_{ 2 }(g)|HCl(sol)\parallel AgCl(s)|Ag$$
  • $$Pt/{ H }_{ 2 }(g)|KCl(sol)\parallel AgCl(s)|Ag$$
In the galvanic cell, $$Cu|{ Cu }^{ 2+ }(1M)\parallel { Ag }^{ + }(1M)|Ag$$, the electrons will travel in the external circuit:
  • from $$Ag$$ to $$Cu$$
  • from $$Cu$$ to $$Ag$$
  • electrons do not travel in the external circuit
  • none of these
Which of the following facts about the chemical cell and concentration cell is correct?
  • Chemical cell is an electrolytic cell whereas concentration cell is a galvanic cell
  • Chemical cell has an overall cell reaction whereas the concentration cell has no overall reaction.
  • Two half cells of both the chemical and concentration cells are chemically different
  • $${E}_{cell}$$ equations (Nernst equation) of both the cells have the therm $${E}_{cell}^{o}$$
One coulomb is the charge of
  • $$1$$ mole of electrons
  • $$\dfrac{1}{96500}$$ mole of electrons
  • $$\% 500$$ moles of electrons
  • $$none\ of\ these$$
Two electrolytic cells containing $$CuSO_{4}$$ and $$AgNO_{4}$$ respectively are connected in series and a current is passed through them unit 1 mg of copper is deposited in the first cell. The amount of silver deposited in the second cell during this time is approximately 
[ Atomic weight of copper and silver are respectively 63.57 and 107.88] 
  • $$3.4 mg$$
  • $$5.1 mg$$
  • $$6.8 mg$$
  • $$1.7 mg$$
Resistance of a voltameter is 2$$\Omega $$, it is connected in series to a battery of 10 V through a resistance of 3$$\Omega $$ . In a certain time mass deposited on cathode is 1 gm. Now the voltameter and the 3$$\Omega $$resistance are connected in parallel with the battery. Increase in the deposited mass on cathode in the same time will be
  • 0
  • 1.5 gm
  • 2.5 gm
  • 2 gm
The amount of charge required to liberate 9 gm of aluminium ( atomic weight = 27 and valency = 3 ) in the process of electrolysis is ( Faraday's number = 96500 coulombs/gm equivalent)
  • 321660 coulombs
  • 69500 coulombs
  • 289500 coulombs
  • 96500 coulombs
$$E_n = -\dfrac{313.6}{n^2}$$, if the value of $$E_i = -38.84$$ to which value 'n' corresponds?
  • 2
  • 4
  • 1
  • 3
If redox reaction takes place in cell then electromotive force (e.m.f) of cell will be:
  • positive
  • negative
  • zero
  • one
Which of the following mixtures represents rusting of iron?
  • FeO and Fe(OH)$$_3$$
  • FeO and Fe(OH)$$_2$$
  • Fe$$_2$$O$$_3$$ and Fe(OH)$$_3$$
  • Fe$$_3$$O$$_4$$ and Fe(OH)$$_2$$
A cell reaction would be spontaneous if the cell potential and $$ \Delta_{r} G $$ are respectively:
  • positive and negative
  • negative , negative
  • zero ,zero
  • positive , zero
Which of the following statements is correct?
  • $$E_{cell}$$ and $$\Delta _rG$$ of a cell reaction,both are extensive properties.
  • $$E_{cell}$$ and $$\Delta _rG$$ of a cell reaction, both are intensive properties.
  • $$E_{cell}$$ is an intensive property, while $$\Delta _rG$$ of a cell reaction is an extensive property.
  • $$E_{cell}$$ is an extensive property, while $$\Delta _rG$$ of a cell reaction is an intensive property.
Standard electrode potential data are useful for understanding the suitability of an oxidant in a redox titration. Some half cell reactions and their standard potentials are given below:  $$MnO^{-}_4(aq)+8H^{+}(aq)+6e^{-} \longrightarrow $$  $$ \mathrm{Mn}^{2+}(a q)+4 \mathrm{H}_{2} \mathrm{O}(l) \mathrm{E}^{\circ}=1.51 \mathrm{V} $$
$$ \mathrm{Cr}_{2} \mathrm{O}_{7}^{2-}(a q)+14 \mathrm{H}^{+}(a q)+6 e^{-} \longrightarrow $$ $$ 2 \mathrm{Cr}^{3+}(a q)+7 \mathrm{H}_{2} \mathrm{O}(l) ; \mathrm{E}^{\circ}=1 \cdot 38 \mathrm{V} $$
$$ \mathrm{Fe}^{3+}(a q)+e^{-} \longrightarrow \mathrm{Fe}^{2+}(a q) ; \mathrm{E}^{\circ}=0.77 \mathrm{V} $$
$$ \mathrm{Cl}_{2}(g)+2 e^{-} \rightarrow 2 \mathrm{Cl}^{-}(a q) ; \mathrm{E}^{\circ}=1 \cdot 40 \mathrm{V} $$

Identify the only incorrect statement regarding the quantitative estimation of aqueous
$$ \mathrm{Fe}\left(\mathrm{NO}_{3}\right)_{2} $$
  • $$ \mathrm{MnO}_{4}^{-} $$ can be used in aqueous $$HCl$$
  • $$ \mathrm{Cr}_{2} \mathrm{O}_{7}^{2-} $$ can be used in aqueous $$HCl$$
  • $$ \mathrm{MnO}_{4}^{-} $$ can be used in aqueous $$ \mathrm{H}_{2} \mathrm{SO}_{4} $$
  • $$ \mathrm{Cr}_{2} \mathrm{O}_{7}^{2-} $$ can be used in aqueous $$ \mathrm{H}_{2} \mathrm{SO}_{4} $$
Which of the following is displaced by Fe ?
  • Ag
  • Zn
  • Na
  • None of these
0:0:1


Answered Not Answered Not Visited Correct : 0 Incorrect : 0

Practice Class 12 Engineering Chemistry Quiz Questions and Answers