CBSE Questions for Class 12 Engineering Chemistry Electrochemistry Quiz 5 - MCQExams.com

The decomposition of chemical compound in the aqueous or fused state by passing direct electric current is known as :
  • electricity
  • electrolyte
  • electrolysis
  • non-electrolysis
Chemical compounds which conduct electricity in the fused or in aqueous solution state and undergo chemical decomposition due to the flow of current through it are known as :
  • electrolytes
  • non-electrolytes
  • weak electrolytes
  • all of the above
Which of the following is an example of strong electrolyte?
  • $$HCl_{(aq)}\rightarrow H^{+}+Cl^{-}$$
  • $$KOH\rightarrow K^{+}+OH^{-}$$
  • $$AgNO_3\rightarrow Ag^{+}+NO_3\,^{-}$$
  • all of the above
Which of the following statement is correct?
  • $$E_{cell}$$ and $$\triangle_{r}G$$ of cell reaction both are extensive properties
  • $$E_{cell}$$ and $$\triangle_{r}G$$ of cell reaction both are intensive properties
  • $$E_{cell}$$ in the intensive property while $$\triangle_{r}G$$ of cell reaction is an extensive property.
  • $$E_{cell}$$ in the intensive property while $$\triangle_{r}G$$ of cell reaction is an intensive property.
Assertion: The anions in an electrolytic cell migrate to the cathode.
Reason:  Positively charged ions are attracted to the negatively charged cathode in an electrolytic cell.

  • Both Assertion and Reason are true and Reason is the correct explanation of Assertion

  • Both Assertion and Reason are true but Reason is not the correct explanation of Assertion

  • Assertion is true but Reason is false

  • Assertion is false but Reason is true

  • Both Assertion and Reason are false

Which instrument is used for the completion of the circuit of an electrochemical cell?
  • Conductivity tester
  • Salt bridge
  • Thermometer
  • Buret
  • Graduated cylinder
In an electrochemical cell, cathode is :
  • always neutral
  • always positive
  • the electrode at which reduction takes place
  • always negative
If the $$\Delta$$G of a cell reaction, $$AgCl+e^-\rightarrow Ag+Cl^-$$ is $$-21.20$$ kJ, the standard emf of cell is
  • $$0.239$$V
  • $$0.220$$V
  • $$-0.320$$V
  • $$-0.110$$V
Which of the following comes out at the anode during electrolysis of copper chloride?
  • Copper
  • Hydrogen
  • Copper chloride
  • Chlorine
On the basis of the information available from the  reaction$$\dfrac { 4 }{ 3 } { Al }+O_{ 2 }\rightarrow\dfrac { 2 }{ 3 } { Al }_{ 2 }{ O }_{ 3 },$$$$\triangle G=-827KJ{ mol }^{ -1 }of{ O }_{ 2 }$$ The minimum e.m.f. required to carry out an electrolysis of$$\left( F=96500C{ mol }^{ -1 } \right)$$
  • $$2.14\ V$$
  • $$4.28\ V$$
  • $$6.42\ V$$
  • $$8.56\ V$$
When $$9.65$$ ampere current was passed for $$1.0$$ hour into nitrobenzene in acidic medium, the amount of p-aminophenol produced is:
  • $$109.0\ g$$
  • $$98.1\ g$$
  • $$9.81\ g$$
  • $$10.9\ g$$
The charge required for the reduction of 1 mol of  $${\text{MnO}}_{\text{4}}^{\text{ - }}$$ to $${\text{Mn}}{{\text{O}}_2}$$ is:
  • 1 F
  • 3 F
  • 5 F
  • 7 F
Hydrogen-oxygen fuel cells are used in space-craft to supply:
  • Illumination
  • Hydrogen
  • Oxygen
  • Water
Unit of Faraday is
  • Ampere
  • Coulomb
  • Coulomb $$mole^{-1}$$
  • Coulomb $$sec^{-1}$$
Faraday has the dimensions of
  • Coulombs
  • Coulombs equivalent
  • Coulombs per equivalent
  • Coulombs per degree Kelvin
The value of one Faraday is
  • $$95500\ C\ mol^{-1}$$
  • $$96550\ C\ mol^{-1}$$
  • $$96500\ C\ mol^{-1}$$
  • $$98500\ C\ mol^{-1}$$
Faraday constant
  • Is a numerical constant
  • Depends on equivalent
  • Depends upon the current passed
  • Depends on the number of electrons
Which of the following statement is true for a electrochemical cell? 
  • $$H_2$$ is cathode and $$Cu$$ is anode
  • $$H_2$$ is anode and $$Cu$$ is cathode
  • Reduction occurs at $$H_2$$ electrode
  • Oxidation occurs at $$Cu$$ electrode
In an electrochemical cell___________
  • potential energy changes into kinetic energy
  • kinetic energy changes into potential energy
  • chemical energy changes into electrical energy
  • electrical energy changes into chemical energy
Which of the following statements about galvanic cell is incorrect?
  • Anode is positive
  • Oxidation occurs at the electrode with lower reduction potential
  • Cathode is positive
  • Reduction occurs at cathode
 In a galvanic cell is anode is ______
  • Negative
  • Positive
  • No charge
  • Sometimes negative and Sometimes Positive
Molten sodium chloride conducts electricity due to presence of: 
  • free electrons
  • free ions
  • free molecule
  • atoms of sodium and chlorine
What makes the electric current flow through electric solution  ?
  • Only free electrons
  • Only positive ions.
  • Only negative ions
  • Positive and negative ions
If a half cell reaction, $$ A+e^{-} \longrightarrow A^{-} $$ has a large negative reduction potential, it follows that
  • $$ \mathrm{A} $$ is easily reduced
  • $$A $$ is readily oxidized
  • $$ \mathrm{A}^{-} $$ is readily reduced
  • $$ \mathrm{A}^{-} $$ is readily oxidised.
For the feasibility of a redox reaction in a cell, the emf should be 
  • Positive
  • Fixed
  • Zero
  • Negative
An addition of $$NaOH$$ to $$CH_3COOH$$ solution shows a decrease in conductance of solution.
  • True
  • False
Which of these metals do not corrode?
  • Lead
  • Copper
  • Platinum
  • Silver
Which modifications are necessary to determine resistance of solutions by usual method of conductance measurement?
  • A.C. should be used
  • A conductivity cell is used
  • Galvanometer is replaced by headphone or magic eye arrangement
  • None of the above
The effect of dilution on conductances shows:
  • increase in conductivity
  • increase in equivalent conductivity
  • increase in molar conductivity
  • decrease in conductance
1 volt coulomb is:
  • equal to 1 J
  • a unit of energy
  • equal to 1 J/coulomb
  • equal to $$10^7$$ erg
Which of the following statements is incorrect?
  • Conductance of an electrolytic solution increases with dilution.
  • Conductance of an electrolytic solution decreases with dilution.
  • Conductivity of an electrolytic solution decreases with dilution.
  • Equivalent conductivity of an electrolytic solution increases with dilution.
Assertion: Rusting of Fe is quicker in saline water than in ordinary water.
Reason: Presence of $$Na^+$$ and $$Cl^-$$ ions increase the conductance of the saline water.
  • Both Assertion and Reason are true and Reason is the correct explanation of Assertion
  • Both Assertion and Reason are true but Reason is not the correct explanation of Assertion
  • Assertion is true but Reason is false
  • Assertion is false but Reason is true
  • Both Assertion and Reason are false
The amount of charge carried by $$M^{3-}$$ ion is:
  • $$4.8 \times 10^{-19} C$$
  • $$7.4 \times 10^{-19} C$$
  • $$9.6 \times 10^{-19} C$$
  • none of the above
A shiny brown-coloured element 'X' on heating in air becomes black in colour. Name the element 'X'?
  • Sodium
  • Calcium
  • Copper
  • Aluminium
Assertion: The amount of charge carried by one mole electrons is the same as carried by one mole of $$K^{\oplus}$$ ions.
Reason: one mole electrons and one mole $$K^{\oplus}$$ ions carry one faraday charge each.
  • Both Assertion and Reason are true and Reason is the correct explanation of Assertion
  • Both Assertion and Reason are true but Reason is not the correct explanation of Assertion
  • Assertion is true but Reason is false
  • Assertion is false but Reason is true
  • Both Assertion and Reason are false
Coulomb is the quantity of current defined as:
  • one ampere of current passing for 1 sec
  • one which deposits 0.001118 g of Ag on cathode
  • one which deposits electrochemical equivalence of metal
  • 1/2 ampere current for two second
A Faraday is:
  • the magnitude of the charge of $$1\ mole$$ of electrons
  • the magnitude of the electric dipole
  • a fundamental constant of nature equal to $$6.63 \times 10^{-34}Js/photon$$
  • a constant that accounts for the existence of ions in solution
Which of the following condition is correct for operation of electrolytic cell?
  • $$\triangle G = 0, E = 0$$
  • $$\triangle G < 0, E > 0$$
  • $$\triangle G > 0, E < 0$$
  • $$\triangle G > 0, E > 0$$
The electric charge for electrode deposition of one gram equivalent of a substance is:
  • $$1$$ ampere s$$^{-1}$$
  • $$96500$$ coulomb s$$^{-1}$$
  • $$1$$ ampere hour$$^{-1}$$
  • $$1$$ coulomb s$$^{-1}$$
1 faraday $$=$$ _________.
  • 10000 $$C$$
  • 95000 $$C$$
  • 96.5 $$C$$
  • 96500 $$C$$

In a galvanic cell, electrons flow through connecting wires from:
  • anode to cathode
  • cathode to anode
  • top to bottom
  • anode
What transformation of energy takes place when current is drawn from a cell ?
  • Chemical energy changes to electrical energy
  • Chemical energy changes to heat energy
  • mechanical energy changes to electrical energy
  • Chemical energy changes to mechanical energy
In electrolysis:
  • positive ions move toward the positive electrode and negative ions toward the negative electrode.
  • positive ions move toward the negative electrode and negative ions toward the positive electrode.
  • both ions move toward both the electrodes in equal amounts until they are balanced.
  • none of the above
Resistivity is reciprocal of ______ of an electrolyte.
  • molar conductivity
  • specific conductance
  • conductance
  • specific resistance
Assertion: Dry cell is a primary cell and lead storage cell is a secondary cell.
Reason: A primary cell can only be used once while secondary cells are rechargeable.
  • Both Assertion and Reason are true and Reason is the correct explanation of Assertion
  • Both Assertion and Reason are true but Reason is not the correct explanation of Assertion
  • Assertion is true but Reason is false
  • Assertion is false but Reason is true
  • Both Assertion and Reason are false
The current inside a copper voltameter
  • is half the outside value.
  • is the same as the outside value.
  • is twice the outside value.
  • depends on the concentration of $${CuSO}_{4}$$
When electric current is passed through the copper sulfate solution, free copper ions gets drawn to the electrode connected to the .............. terminal of the battery and gets deposited on it.
  • positive
  • negative
  • does not get attracted
  • data insufficient
On electrolysis, water splits into :
  • Positively charged hydrogen ions and negatively charged oxygen ions.
  • Negatively charged hydrogen ions and positively charged oxygen ions.
  • Hydrogen and oxygen atoms having positive and negative charges respectively.
  • Hydrogen and oxygen atoms having negative and positive charges respectively.
Any article of iron if left in open for some time, acquires a film of brownish substance (rust) having chemical formula:
  • $$Fe_3O_4$$
  • $$Fe_2O_3$$
  • FeO
  • $$Fe(OH)_2$$
What happens when an electrolysis experiment is stopped and the battery terminals are reversed?
  • Electrolysis, will stop immediately.
  • The electrolysis proceeds and the rate of liberation remains the same.
  • The rate of liberation increases.
  • The rate of liberation decreases.
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