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Metallic and electrolytic conduction - class-XII

Description: metallic and electrolytic conduction
Number of Questions: 85
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Tags: electrochemistry chemistry chemical reactions
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Which of the following is an insulator?

  1. Wood

  2. Iron

  3. Graphite

  4. Silver


Correct Option: A
Explanation:

Insulators donot conduct electricity due to the absence of ions or electrons.

Iron is metal therefore has pool of electrons on the surface and is a conductor.
Graphite has extensive $\pi$ electron cloud and is thus a conductor.
Silver is a metal and is a very good conductor of electricity.
Wood is made of organic molecule, thus its an insulator.
Option A is correct

Insulators:

  1. conduct electricity.

  2. do not conduct electricity.

  3. conduct electricity only at low temperatures.

  4. conduct electricity at room temperature.


Correct Option: B

What is [CN-] in a solution prepared by mixing 100ml 0.1M $KCN$ and 100ml 0.1M $HCl$. (Ka of $HCN$ is 510^-6 M)?

  1. $5\times10^{-4} M$

  2. $2\times10^{-6} M$

  3. $2\times10^{-5} M$

  4. $4 \times10^{-6} M$


Correct Option: C

A compass placed in an electric field will be deflected due to:

  1. heating effect of current

  2. magnetic effect of current

  3. conducting effect

  4. resistance of the needle to the electric field


Correct Option: B
Explanation:

An electric current causes a magnetic field around it just like a magnet causes a magnetic field. When you moved the compass near an electric field, the magnetic field produced due to the electric field deflects the compass.


Hence, the correct option is $\text{B}$

Which of the following is a good conductor of electricity?

  1. Tap water

  2. Distilled water

  3. Sea water

  4. Rain water


Correct Option: A,C,D
Explanation:
Sea water, tap water, and rainwater comprise of salt and many other impurities whereas distilled is void of such impurities. 

Those impurities, act as ions and help in the transfer of charge.
 
Hence, they are good conductor of electricity.

Distilled water is highly purified water that does not contain any salts. Hence, it do not conduct electricity.

Therefore, option A, C and D are correct.

Which of the following does not conduct electricity ?

  1. Molten NaoH

  2. Molten KOH

  3. Solid NaCI

  4. Aqueous NaCI


Correct Option: C

A Coordinates complex has the formula $PtCl.2KCl$. Electrical conductance measurements indicate the pressure of three ion in one formulaa unit. Treatment with $AgNO _{3}$ produces no precipiate of $AgCl$. What is the coordinates no of $Pt$ this complex?

  1. $6$

  2. $5$

  3. $4$

  4. $3$


Correct Option: B

An acidic solution of Cu+ salt containing 0.4 g of Cu+ is electrolysed until all the Cu is deposited. The electrolysis is continued for 7 more minutes with volume of the solution kept at 100 ml and the current at 1.2 amp. Calculate volume of the gases evolved at NTP during entire electrolysis( atomic weight of Cu= 63.6)

  1. H2 = 68.32 ; O2 = 85.23 ml

  2. H2 = 40.34 ; O2 =70.12 ml

  3. H2= 51.46 ; O2 = 90.12 ml

  4. H2=58.46 ; O2 = 99.68 ml


Correct Option: D

An electrolytic cell was set up. Distilled water is placed in the cell and battery is switched on. The bulb is also connected through a battery. The bulb will:

  1. glow

  2. not glow

  3. partially glow

  4. none of the above


Correct Option: B
Explanation:

Distilled water is a bad conductor of electricity. It do not contains any impurities to carry the current. So the circuit will not be completed for the bulb to glow.

Which of the following is a good conductor of electricity?

  1. $HCOOH$

  2. $CH _3Cl$

  3. $C _2H _5OH$

  4. $KOH$


Correct Option: D
Explanation:

KOH being a strong base is a good conductor of electricity. 

Which technique should be used to determine if a solution contains a molecular or ionic solute?

  1. Conductivity

  2. Calorimetry

  3. Precipitation

  4. Spectophotometry


Correct Option: A
Explanation:

The presence of ionic solute in a solution can be determined by measuring its conductivity because ions are good conductor of electricity.

The first step in the extraction of Cu from copper pyrites is?

  1. Reduction by carbon

  2. Electrolysis of ore

  3. A Roasting of ore in $O _2$

  4. Magnetic separation


Correct Option: B

Conductivity ($\kappa $) of $0.01M$ $NaCl$ solution is $0.000145S$ ${cm}^{-1}$. What happens to the conductivity if extra $100mL$ of ${H} _{2}O$ be added to the above solution?

  1. Decreases

  2. Increases

  3. Remains unchanged

  4. First increase and then decrease


Correct Option: A

Which of the following is/are always true electroplating ?

  1. Copper is used as cathode

  2. Cathode always gins weight while anode always loses weight

  3. Iron is coated with nickel or chromium to prevent from rusting.

  4. Ammeter reading during. electroplating steadily decreases.


Correct Option: A
Assertion: The conductance of electrolyte solution increases with temperature.
Reason: With increase of temperature the ionic mobility increases.
  1. Both Assertion and Reason are true and Reason is the correct explanation of Assertion

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

  3. Assertion is true but Reason is false

  4. Assertion is false but Reason is true

  5. Both Assertion and Reason are false


Correct Option: A
Explanation:

With increase of temperature the ionic mobility increases.

Arrange the following complexes in order of increasing electrical conductivity.
(I) $[CoCl _3(NH _3) _3]$     (II) $[CoCl(NH _3) _5]CI _2$
(III) $[Co(NH _3) _6]Cl _3$   (IV) $[CoCl _2(NH _3) _]1Cl$ 

  1. III > II > IV > I

  2. II > III > IV > I

  3. II > III > I > IV

  4. III > IV > II > I


Correct Option: A
Explanation:

Electrical conductivity $\times $ no. / moles of ions present after dissociation.

$I$ $\therefore \quad \left[ Co{ Cl } _{ 3 }{ \left( { NH } _{ 3 } \right)  } _{ 3 } \right] $
$II$  $\left[ CoCl{ \left( { NH } _{ 3 } \right)  } _{ 5 } \right] { Cl } _{ 2 }\rightarrow { \left[ CoCl{ \left( { NH } _{ 3 } \right)  } _{ 5 } \right]  }^{ 2+ }+2{ Cl }^{ \left( - \right)  }$
$IV$  $\left[ Co{ Cl } _{ 2 }{ \left( { NH } _{ 3 } \right)  } _{ 4 } \right] Cl\rightarrow { \left[ Co{ Cl } _{ 2 }{ \left( { NH } _{ 3 } \right)  } _{ 4 } \right]  }^{ + }+{ Cl }^{ \left( - \right)  }$
$III$  ${ \left[ Co{ \left( { NH } _{ 3 } \right)  } _{ 6 } \right] Cl } _{ 3 }\rightarrow { \left[ Co{ \left( { NH } _{ 3 } \right)  } _{ 6 } \right]  }^{ 3+ }+3{ Cl }^{ \left( - \right)  }$
Hence the correct answer is,
$\boxed { III>II>IV>I } $

The electric conduction of a salt solution in water depends on the:

  1. shape of molecules

  2. size of its molecules

  3. size of solvent molecules

  4. extent of its ionisation


Correct Option: D
Explanation:

Higher the number of ions in solution, higher would be the conductivity of the solution as the number of charge carriers would increase. Hence, higher the degree of ionization greater would be the number of ions in solution.

Kim Istry was tired and thirsty after her soccer game, so she drank a sports drink that contained electrolytes. Kim is smart girl who known that when electrolytes dissolve in water, they produce solutions that can conduct an electric current. She also knows that the type of bonding in a substance can determined whether or not it is an electrolyte.
Which of the following substances is classified as an electrolyte?

  1. Sodium chloride, $NaCl$

  2. Glucose, $C _{6}H _{12}O _{6}$

  3. Water, $H _{2}O$

  4. Ethanol, $C _{2}H _{5}OH$


Correct Option: A
Explanation:

The electrolyte present in sports drink is sodium chloride.

Conductivity of aqueous solution of an electrolyte depends on:

  1. molecular mass of the electrolyte

  2. boiling point of solvent

  3. degree of ionisation

  4. volume of the solvent


Correct Option: C
Explanation:

Conductivity of an aqueous solution depends on degree of ionization of solute. More is the degree of ionization more will be conductivity. Second, important factor on which conductivity depend is temperature.

Electrical conductivity of $Se$ is negligible in dark but increases to exposure to light. Because of this property it is used in:

  1. photoelectric cells

  2. semiconductors

  3. high voltage batteries

  4. lasers


Correct Option: A
Explanation:

In photoelectric cells, light energy is converted into electrical energy .Thus $Se$ is used in photocells because of its behaviour to become a conductor in presence of light.

Pure water is a good conductor of electricity.

  1. True

  2. False


Correct Option: B
Explanation:

For pure water ${ K } _{ a }=1.8\times { 10 }^{ -16 }$ at $25℃$

Since dissociation constant is very very low.
So pure water doesn't conduct electricity. Because free ions are not present in sufficient amount for conduction.
${ H } _{ 2 }{ O\rightleftharpoons  }{ H }^{ + }+{ OH }^{ - }$ (weak dissociation constant)

Molten sodium chloride conducts electricity due to presence of:

  1. free electrons

  2. free ions

  3. free molecules

  4. free atoms


Correct Option: B
Explanation:
Molten sodium chloride conducts electricity due to the presence of free ions.
In order to conduct electricity a substance must have charge particles, such as electrons and ions, that are free to move freely through it. In the solid state, ionic compounds such as sodium chloride have their ions fixed in position and therefore these ions cannot move so solid ionic compounds cannot conduct electricity. However in the molten state, ions in ionic compounds are free to flow and therefore molten sodium chloride can conduct electricity.

Metallic conduction depends upon which of the following?

  1. The nature of the metal

  2. Number of valence electrons per atom

  3. Density of metal

  4. Temperature


Correct Option: A
Explanation:

For metals the thermal conductivity is mainly a function of the motion of free electrons.As the temperature increases the molecular vibrations increases so they obstruct the free flow of electrons thus reducing conductivity.

How much time is required for the complete decomposition of 2 moles of water using a current of 2 ampere?

  1. 26.805 h

  2. 153.61 h

  3. 107.22 h

  4. None of these


Correct Option: D
Explanation:
Solution:- (D) none of these
$2 {H} _{2}O \longrightarrow 2 {H} _{2} + {O} _{2}$
From the above reaction-
$1$ mole of ${H} _{2}O$ exchanges $2$ moles of electrons, then $2$ moles of ${H} _{2}O$ will exchange $4$ moles of electrons.
From Faraday's law of electrolysis,
$q = nF$
$\Rightarrow i \times t = nF \; \left( \because q = i \times t \right)$
$\Rightarrow t = \cfrac{nF}{i} = \cfrac{4 \times 96500}{2} = 193000 \; s = 53.61 \; hr$
Hence the time required is $53.61$ hours.

A dilute solution of $H _2SO _4$ was electrolyzed by passing a current of 2 amp. The time required for formation of 0.5 mole of oxygen is:

  1. 26.8 hours

  2. 13.4 hours

  3. 6.7 hours

  4. 28.6 hours


Correct Option: A
Explanation:
Let current of $2$ amp is passed through the solutions for $t$ seconds
$\therefore$   Charge passed $=2\times t$

$\therefore$   moles of electrons passed $=\dfrac { 2t }{ 96500 } $
At anode :

${ 2OH }^{ \left( - \right)  }\rightarrow 1/2{ O } _{ 2 }+{ H } _{ 2 }O+{ 2e }^{ - }$
$\therefore$   moles of ${ O } _{ 2 }$ released at anode $=\dfrac { 2t }{ 96500 } \times \dfrac { 1 }{ 4 } $

$\therefore$   $\dfrac { 2t }{ 96500 } \times \dfrac { 1 }{ 4 } =0.5$
$\Rightarrow t=96500$ secs $=26.8$ hours

$\therefore$   The time required for formation of $0.5$ mole of ${ O } _{ 2 }$ is $26.8$ hours.

Hence, the correct option is A.

A current being passed for two hour through a solution of an acid liberating 11.2 litre of oxygen at NTP at anode. What will be the amount of copper deposited at the cathode by the same current when passed through a solution of copper sulphate for the same time?

  1. 16 g

  2. 63 g

  3. 31.5 g

  4. 8 g


Correct Option: B
Explanation:

Solution:- (B) $63 \; g$

At STP,
$1$ mole of oxygen gas $= 32 \; g = 22.4 \; L$
Therefore,
$11.2 \; L$ of ${O} _{2} = \cfrac{32}{22.4} \times 11.2 = 16 \; g$
Therefore,
$\cfrac{{M} _{Cu}}{{M} _{{O} _{2}}} = \cfrac{{E} _{Cu}}{{E} _{O}}$
$\Rightarrow \cfrac{{M} _{Cu}}{16} = \cfrac{\left( \cfrac{63}{2} \right)}{\left( \cfrac{16}{2} \right)}$
$\Rightarrow {M} _{Cu} = 63 \; g$
Hence the amount of copper deposited at the cathode is $63 \; g$.

A current of 9.65 Ampere flowing for 10 minutes deposits 3 g of metal which is monovalent, the atomic mass of metal is a:

  1. 10

  2. 50

  3. 30

  4. 96.5


Correct Option: B
Explanation:

Solution:- (B) $50$

Weight of metal deposited $= 3 \; g$
Quantity of electricity passed $\left( q \right)$-
$q = I \times t$
Given:-
$I = 9.65 A$
$t = 10 \; min = 10 \times 60 = 600 \; sec$
$\therefore q = 9.65 \times 600 = 5790 \; C$
Now, as we know that,
Eq. wt. of metal $= \cfrac{\text{Weight of metal}}{q} \times F$
$\Rightarrow$ Eq. wt. of metal $= \cfrac{3}{5790} \times 96500 = 50 \; g$
As the metal is monovalent, atomic weight of metal will be equal to its equivalent weight.
Therefore,
Atomic weight of metal $= 50 \; g$

Which of the following ($1\ M$) conducts more electricity?

  1. Sulphuric acid

  2. Boric acid

  3. Nitric acid

  4. Phosphorous acid


Correct Option: A

In metallic conductor the current is conducted by flow of:

  1. ions

  2. atoms

  3. electrons

  4. molecules


Correct Option: C
Explanation:

In metallic conductor the current is conducted by flow of free electrons.Ions contain the free electron therefore they conducts the electricity.

The charge required to deposit 40.5 g of Al(atomic mass=27.0 g) from the fused ${ Al } _{ 2 }{ \left( { SO } _{ 4 } \right) } _{ 3 }$ is :

  1. $4.34\times { 10 }^{ 5 }C$

  2. $43.4\times { 10 }^{ 5 }C$

  3. $1.44\times { 10 }^{ 5 }C$

  4. None of these


Correct Option: A

Electrolytic conductivity of $0.3 M$ solution of $KCI$ at $298 K $is $3.72$ x ${10}^{-2}Scm^{-1}$.Calculate its molar conductivity ($S cm^{2} mol ^{-1}$) 

  1. $124$

  2. $30.56$

  3. $192$

  4. $185$


Correct Option: A
Explanation:

Given,

$k=3.72\times 10^{-2}\ Scm^{-1}$
$c=0.3M$

Molar conductivity($m$) is given by,

$m=\dfrac{k\times 1000}{c}$

$\Rightarrow m=\dfrac{3.72\times 10^{-2}\times 1000}{0.3}$

$\Rightarrow m=124\ S\ cm^2mol^{-1}$

Resistance of decimolar solution is 50 ohm. If electrodes of surface area 0.0004 $m^2$ each are placed at a distance of 0.02 m then conductivity of solution is : 

  1. $1 \,s\,cm^{-1}$

  2. $0.01 \,s\,cm^{-1}$

  3. $0.001 \,s\,cm^{-1}$

  4. $10 \,s\,cm^{-1}$


Correct Option: C

Which statement is not correct ?

  1. Conductance of an electrolytic solution increase with dilution

  2. Conductance of an electrolytic solution decrease with dilution

  3. specific conductance of an electrolytic solution decrease with dilution

  4. Equivalent conductance of an electrolytic solution increase with dilution


Correct Option: C

Pure water consists almost entirely of:

  1. molecules

  2. ions

  3. atoms

  4. ions and molecules


Correct Option: A
Explanation:

Water has very low ionisation constant so it dissociates very low and pure water is consists almost entirely of molecules.

Molten potassium chloride conducts electricity due to the presence of  _______ .

  1. free electron

  2. free ions

  3. free molecules

  4. atom of potassium & chloride


Correct Option: B

Which of the following solid is an electronic conductor?

  1. $NaCl$

  2. Diamond

  3. $CuS$

  4. $KCl$


Correct Option: C
Explanation:

Only CuS solid conducts electricity. NaCl and KCl are electrolytic conductor and diamond is non-conductor.

Hence, correct option is C.

We can expect that pure water:

  1. will not normally conduct electricity

  2. will normally conduct electricity

  3. slightly conduct electricity

  4. completely conduct electricity


Correct Option: A
Explanation:

Water has very low ionisation constant so it dissociates very low and pure water  consists almost entirely of molecules; as no of ions are very less in pure water so normally it will not conduct electricity.

Which modifications are necessary to determine the resistance of solution by the usual method of measurements on Wheatstone's bridge principle?

  1. A.C. should be used

  2. A conductivity cell is used

  3. Galvanometer is replaced by magic eye or headphone arrangement

  4. All of the above


Correct Option: D
Explanation:

All of the following modifications are necessary to determine the resistance of solution by the usual method of measurements on Wheatstone's bridge principle.


(A) A.C. should be used.
(B) A conductivity cell is used.
(C) The galvanometer is replaced by magic eye or headphone arrangement.

If D.C. is used, electrolyte solution will go electrolysis and the change in concentration during the passage of current will not allow reaching the steady value of the null point. In A.C. galvanometer does not work. Also to put the solution at one end in the gap of the meter bridge, a conductivity cell is needed.

Hence, the correct option is $D$

Assertion: Nickel is a metal and it conducts electricity through its valence shell electrons.
Reason: Nickel sulphate solution conducts electricity through its ions.
  1. Both Assertion and Reason are true and Reason is the correct explanation of Assertion

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

  3. Assertion is true but Reason is false

  4. Assertion is false but Reason is true

  5. Both Assertion and Reason are false


Correct Option: B
Explanation:

Nickel is a metal and it conducts electricity through its valence shell electrons while nickel sulphate solution conducts electricity through its ions (formed by dissociation of nickel sulphate solutions).

Which one of the following solution will conduct electricity?

  1. Sugar in water

  2. Sugar in ethyl alcohol

  3. Iodine in ethyl alcohol

  4. Magnesium chloride water


Correct Option: D
Explanation:

Solution which contains free ions conducts electricity.

Since, Magnesium Chloride aqueous solution will have Mg ions. Hence, it will conduct electricity

A solution of sodium in liquid ammonia at $-33^oC$ conducts electricity. On cooling, the conductivity of this solution _______.

  1. decreases

  2. increases

  3. remains same

  4. becomes 0


Correct Option: A
Explanation:

A solution of sodium in liquid ammonia at $-33^oC$ conducts electricity. On cooling, the conductivity of this solution ...... The conductivity of the solution is due to presence of ammoniated electrons. With decrease in the temperature, the mobility of ammoniated electrons decreases due to which the electrical conductivity decreases.

An aluminium wire is:

  1. non-electrolyte

  2. weak electrolyte

  3. metallic conductor

  4. none of these


Correct Option: C
Explanation:

Aluminium is metal so its wire will act as metallic conductor and it conducts electricity due to valence shell electrons.

Examine the following statement sand select the correct option.
A : Electrolytic conduction is a physical change.
B : In Electrolytic conduction, positive as well as negative ions conduct electricity.

  1. Both A and B are true

  2. Both A and B are false

  3. A is true and B is false

  4. A is false but B is true


Correct Option: D
Explanation:

Electrolytic conduction is a chemical change. It involves a redox reaction.
In electrolytic conduction, positive as well as negative ions conduct electricity.
For example, during electrolysis of molten NaCl, both $Na^+$ and $Cl^-$ ions are involved in the conduction of electricity.
Thus, A is false but B is true.

Assertion: In electrolysis of water, ions are not discharged at electrodes.
Reason: The current-carrying ions in an electrolytic cell are not necessarily discharged at the electrodes.
  1. Both Assertion and Reason are true and Reason is the correct explanation of Assertion

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

  3. Assertion is true but Reason is false

  4. Assertion is false but Reason is true

  5. Both Assertion and Reason are false


Correct Option: A
Explanation:

The current-carrying ions in an electrolytic cell are not necessarily discharged at the electrodes. This is true for the electrolysis of aqueous salt solutions in which water is involved in the electrode reactions and not the current carrying ions.
$2H _2O \rightarrow O _2 + 4H^+ +4e^-$    oxidation
$2H _2O + 2e^- \rightarrow H _2 +2OH^-$   reduction

Assertion: Electrolytic conductance increases with the increase of temperature
Reason: Metallic conductance decreases with the increase in temperature.

Choose the correct option.
  1. Both Assertion and Reason are true and Reason is the correct explanation of Assertion

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

  3. Assertion is true but Reason is false

  4. Assertion is false but Reason is true

  5. Both Assertion and Reason are false


Correct Option: B
Explanation:

The conductivity of an electrolyte depends on the temperature. With an increase in temperature, the conductivity of an electrolyte increases.This is due to increase in ionic mobility. 


For metals, the thermal conductivity is mainly a function of the motion of free electrons. As the temperature increases, the molecular vibrations increase (in turn increasing the mean free path of molecules). So, they obstruct the flow of free electrons, thus reducing the conductivity.

Which of the following will conduct electricity?

  1. Ammonium acetate

  2. Ammonium hydroxide

  3. Sodium hydroxide

  4. formic acid


Correct Option: A,C
Explanation:

Ammonium acetate is a salt. Salts conduct electricity due to complete dissociation. Ammonium hydroxide is a weak base and does not conduct electricity. Sodium hydroxide is a strong base and conducts electricity. Formic acid is a weak acid and does not conduct electricity. 

An electrolytic cell was set up. Dilute $HCl$ is placed in the cell and battery is switched on. The bulb is also connected through a battery. The bulb will:

  1. glow brightly

  2. not glow

  3. depends on amount of HCl

  4. none of the above


Correct Option: A
Explanation:

$HCl$ is a strong acid and it has ions to carry the current. So the circuit will be completed and the bulb will glow brightly.

Which of the following is a poor conductor of electricity?

  1. $NH _4OH$

  2. $HCl$

  3. $CH _3COOH$

  4. $NaOH$


Correct Option: A,C
Explanation:

Ammonium hydroxide and acetic acid are weak bases and acid respectively. Hence, they are poor conductors. 

In which of the following cases, conductivity decreases with an increase in temperature?

  1. Fused $NaCl$

  2. $Cd$

  3. $NaOH$

  4. ${NH} _{4}OH$


Correct Option: B
Explanation:

The electrical conductivity of a conductor will decrease with an increase in temperature. But for acids bases and salts raising the temperature gives more energy to the ions making them move faster, and hence increasing the conductivity.

Which does not show electrical conductance?

  1. Sodium

  2. Diamond

  3. Potassium

  4. Graphite


Correct Option: B,D
Explanation:

Sodium, potassium and Graphite all three are electrical conductor except Diamond which is an insulator of electric current.

Which of the following will conduct electricity?

  1. distilled water

  2. potable water

  3. well water

  4. none of the above


Correct Option: C
Explanation:

Well water conducts electricity due to the presence of ions.

Which of the following solutions contains the greatest number of ions assuming that each solute is fully ionized?

  1. $1$ cm$^{-3}$ of $0.2M$ ${Na} _{2}{SO} _{4}$

  2. $1$ cm$^{-3}$ of $0.2M$ $Ca{Cl} _{2}$

  3. $1$ cm$^{-3}$ of $0.2M$ $NaCl$

  4. $1$ cm$^{-3}$ of $0.2M$ ${Cr} _{2}{({SO} _{4})} _{3}$


Correct Option: D
Explanation:

No. of ions in 11 molecule of $Na _2SO _4=3$ 

No. of ions in 11 molecule of $CaCl _2=3$
No. of ions in 11 molecule of $NaCl=2$
No. of ions in 11 molecule of $Cr _2(SO _4) _3=5$
As the molarity and volume is same for all the given substances, number of ions will be greatest for the compound having greatest number of ions in one molecule. Therefore, $Cr _2(SO _4) _3$ will have the greatest number of ions.

An electrolytic cell was set up. Water is placed in the cell and battery is switched on. The bulb is also connected through a battery. The bulb will:

  1. glow.

  2. not glow.

  3. depends on the amount of water.

  4. None of the above.


Correct Option: A
Explanation:

Water has some impurities in it. So the impurities will carry the current and the bulb will glow.

An electrolytic cell was set up. Ammonium hydroxide is placed in the cell and battery is switched on. The bulb is also connected through a battery. The bulb will:

  1. glow brightly

  2. glow dimly

  3. not glow

  4. depends on the amount of ammonium hydroxide


Correct Option: B
Explanation:

Ammonium hydroxide is a weak base so it has less ions to carry the current. So the circuit will be completed and the bulb will glow dimly.

The electrical conductivity of a solution depends upon :

  1. its dilution

  2. its pressure

  3. the number of ions

  4. its temperature


Correct Option: C

Which of the following is not a property of metallic conduction?

  1. The flow of electricity takes place by flow of electrons

  2. There is no decomposition of the parent metal

  3. Metals are good conductors of electricity in solid state and in the molten state

  4. None of the above


Correct Option: D
Explanation:
The properties of metallic conduction are:
1. The flow of electricity takes place by a flow of electrons.
2. There is no decomposition of the parent metal
3. Metals are good conductors of electricity in solid state and in the molten state

Conduction of electricity takes place due to the presence of :

  1. free atoms

  2. free ions

  3. molecules

  4. gas dissolved in water


Correct Option: B
Explanation:

Conduction of electricity takes place due to the presence of free ions.

Which of the following sentences is/are true?

  1. Electrolytic conduction involves chemical changes

  2. Metallic conduction does not involve chemical changes

  3. Both of the above

  4. None of the above


Correct Option: C
Explanation:

Electrolytic conduction occurs when a voltage is applied across the electrodes dipped in the electrolytic solution. The ions present in the electrolyte moves. The cations move towards the cathode. In the cathode the cations undergo reduction. The anions move towards the anode. In the anode the anions undergo oxidation. Thus electrolytic conduction accompanies a chemical change.
But no such chemical change occurs in case of metallic conduction.

Assertion: A 0.2M solution of carbonic acid is a weaker conductor of electricity than a 0.2M solution of $HBr$.

Reason: In solutions with the same concentration of solute molecules, $H _2CO _3$ is less dissociated than $HBr$.

  1. The Assertion and Reason are correct and Reason is the correct explanation of Assertion

  2. Both the Assertion and Reason are correct and Reason is NOT the correct explanation of Assertion

  3. The Assertion is correct but Reason is not correct

  4. The Assertion is not correct but Reason is correct

  5. Both the Assertion and Reason are not correct


Correct Option: A
Explanation:

Option A is the correct answer.

$ {HBr} $ dissociates completely in a solution forming $ {H}^{+} $ and $ {Br}^{-} $ ions. Whereas, $ {H} _{2}{C}{O} _{3} $ partially dissociates in a solution forming $ {H}^{+} $ and $ {HCO} _{3}^{-} $ ions. Thus in the same concentration of both the acids $ {HBr} $  is a stronger acid than $ {H} _{2}{C}{O} _{3} $. 
As $ {HBr} $  dissociates completely,  $ {H}^{+} $ ion concentration is more in this case, and hence $ {HBr} $ is a good conductor of electricity.

Which of the following sentences about conduction is/are true?

  1. Electrolytic conduction involves transfer of matter

  2. Metallic conduction does not involve transfer of matter

  3. Both of the above

  4. None of the above


Correct Option: C
Explanation:

In electrolytic conduction, a voltage is applied across the electrodes dipped into the electrolytic solution. There are ions present in electrolytic solution. Because of the voltage applied, electric current will flow in the solution. The ions will move in the solution. The cations will move towards the cathode, whereas the anions will move towards the anode.
Thus in electrolytic conduction mass is transferred in the form of ions.
Whereas, no such transfer of mass occur in metallic conduction. It is just the flow of electrons. 

 Which of the following statements is true about electrolytic conduction?

  1. Occurs due to flow of electrons

  2. Occurs due to flow of ions

  3. Both of the above

  4. None of the above


Correct Option: B
Explanation:

In an electrolytic solution when a voltage is applied across the electrodes dipped into the solution, the ions present in the electrolyte move. The cations move towards the cathode, whereas the anions move towards the anode and thus electric current flows through the electrolytic solution. Thus electrolytic conduction occurs because of the flow of ions.

Which of the following would produce a highly conductive aqueous solution?

  1. Cyclohexane

  2. Hydrochloric acid

  3. Benzene

  4. Sucrose

  5. Acetic acid


Correct Option: B
Explanation:

Hydrochloric acid acid is a ionic compound which can easily dissociates into $H^+$ and $Cl^-$ ionsand gives high conductivity.

Metals are good conductors of electricity because of which of the following reasons?

  1. Metals have free electrons

  2. Metals have free ions

  3. Metals have free atoms

  4. None of the above


Correct Option: A
Explanation:

Metal atoms have outer electrons which are not tied to any other atom. Thus metals have free electrons. This electron can move freely in the metal structure. Because of the presence of this free electron metals can conduct electricity. Electricity is the flow of electrons.

In a conduction process,change of mass was observed. The conduction type can be:

  1. metallic

  2. electrolytic

  3. may be any one of these

  4. none of these


Correct Option: B
Explanation:

In a conduction process,change of mass was observed. The conduction type can be electrolytic as electrolytic conduction takes place due to flow of ions thus electrolytic conduction involves transfer of matter.

Which of the following sentences about conduction is/are true?

  1. Metallic conduction decreases with increase in temperature

  2. Electrolytic conduction increases with increase in temperature

  3. Both of the above

  4. None of the above


Correct Option: C
Explanation:

Electrolytic conduction occurs because of the flow of ions. As the temperature increases, the degree of ionization of the electrolyte also increases. Hence the flow of ions also increases. So, electrolytic conduction increases with the increase in temperature.
Metallic conduction occurs because of the flow of electrons. As the temperature rises the metal atoms vibrate more. And hence the resistance offered by the moving electrons also increases. Because of this resistance, the conduction decreases. So metallic conduction decreases with increase in temperature.

Which among the following solutions is NOT used in determination of the cell constant?

  1. ${ 10 }^{ -2 }MKCl$

  2. ${ 10 }^{ -1 }MKCl$

  3. $1 M KCl$

  4. Saturated $KCl$


Correct Option: D

Metallic conduction involves:

  1. no chemical change

  2. flow of electrons

  3. transfer of matter

  4. conductance decreases with increase in temperature


Correct Option: B,D
Explanation:

The substances which allow the flow of electric current are called conductors. The good metal conductors are copper, silver, tin, etc. 


It is due to the flow of electrons. It is not accompanied by the decomposition of the substance, only physical changes occur. It also does not involve the transfer of matter it is due to the flow of electrons. 

Conductivity decreases with an increase in temperature due to an increase in the number of collisions.

Hence, the correct options are $B$ and $D$

In Death valley,California,a conduction process was going on in an air conditioned room maintained at $30^0$.Suddenly there was a power cut and temperature started to rise and it was found that the conduction process got slower.The conduction type can be:

  1. electrolytic

  2. metallic

  3. any of these

  4. none of these


Correct Option: B
Explanation:

As temperature rises, thermal conductivity of metals decreases due to increase in molecular collisions.

Ionic conductance of ${ H }^{ + }$ and ${ SO } _{ 4 }^{ 2- }$ are $x$ and $yS\ { cm }^{ 2 }\ { mol }^{ -1 }$. Hence, equivalent conductivity of ${ H } _{ 2 }{ SO } _{ 4 }$ is:

  1. $2x+\cfrac { y }{ 2 } $

  2. $x+\cfrac { y }{ 2 } $

  3. $\cfrac { x }{ 2 } +y$

  4. $\cfrac { x }{ 2 } +\cfrac { y }{ 2 } $


Correct Option: A
Explanation:

Equivalent conductance can be defined as the conductance produce by an equivalent of ion present in the solution.

For ${ H }^{ + }$, no.of ${ e }^{ - }$ change $=1$
For ${ SO } _{ 4 }^{ 2- }$, no.of ${ e }^{ - }$ change $=2$
Thus equivalent conductance of ${ H } _{ 2 }{ SO } _{ 4 }$
${ H } _{ 2 }{ SO } _{ 4 }$ $\rightleftharpoons 2{ H }^{ + }+{ SO } _{ 4 }^{ 2- }$
Eg Conductance $=\cfrac { 2[Ionic\quad conductance\quad of\quad { H }^{ + }] }{ nf } +\cfrac { Ionic\quad Conductance\quad of\quad { SO } _{ 4 }^{ 2- } }{ nf } $
Eg. Conductance $=2\times \cfrac { x }{ 1 } s{ cm }^{ 2 }+\cfrac { y }{ 2 } s{ cm }^{ 2 }$
Eg. Conductance $=2x+\cfrac { y }{ 2 }$

In passing $3\ F$ of electricity through three electrolytic cells connected in series containing $Ag^{\oplus}, Ca^{2+}$, and $Al^{3+}$ ions, respectively. The molar ratio in which the three metal ions are liberated at the electrodes is:

  1. $1 : 2 : 3$

  2. $2 : 3 : 1$

  3. $6 : 3 : 2$

  4. $3 : 4 : 2$


Correct Option: C
Explanation:

For all the solution $Q=i\times t$ is same,

${ n } _{ Ag }=\cfrac { Q }{ nF } =\cfrac { Q }{ F } ({ Ag }^{ + }+{ e }^{ - }\longrightarrow Ag)$
${ n } _{ Ca }=\cfrac { Q }{ 2F } ({ Ca }^{ 2+ }+2{ e }^{ - }\rightarrow Ca)$
${ n } _{ Al }=\cfrac { Q }{ 3F } ({ Al }^{ 3+ }+3{ e }^{ - }\rightarrow Al)$
$\therefore $ ${ n } _{ Ag }:{ n } _{ Ca }:{ n } _{ Al }=1:\cfrac { 1 }{ 2 } :\cfrac { 1 }{ 3 } =6:3:2$
$\therefore $   Molar ratio$=6:3:2$.

Which of the following statement is incorrect with respect to metallic or electronic conductivity ?

  1. Metallic conductivity depends on the number of electrons in the valence shell of an atom of metal

  2. Metallic conductivity depends on the structure of metal and its characteristics

  3. The electrical conductivity of metal increases with increase in temperature

  4. There is no change in the structure of metal during electrical conduction


Correct Option: C
Explanation:

Metallic or electronic conductivity is due to the presence of free electrons or/and holes (positive charge). It depends upon:
(i) Number of valence electrons present in the metal 
(ii) Structure and nature (characteristic) of metal 
(iii) Density of metal 
(iv) Temperature 


With increase in temperature, electronic conductivity decreases because the arrangement of electrons gets disturbed. Metallic conductivity does not affect the structure of the metal. 

At infinite dilution equivalent conductances of $B{ a }^{ +2 }$ & $C{ 1 }^{ - }$ ions are $127$ & $76\ oh{ m }^{ -1 }c{ m }^{ -1 }\ e{ q }^{ -1 }$ respectively. Equivalent conductance of $BaCl _{ 2 }$ at infinite dilution is:

  1. $139.5$

  2. $101.5$

  3. $203$

  4. $279$


Correct Option: D
Explanation:

${ \Lambda  } _{ eq }^{ \infty  }\left( { Ba }^{ 2+ } \right) =127{ \Omega  }^{ -1 }{ cm }^{ -1 }{ eq }^{ -1 }\ { \Lambda  } _{ eq }^{ \infty  }\left( { Cl }^{ - } \right) =76{ \Omega  }^{ -1 }{ cm }^{ -1 }{ eq }^{ -1 }\ { \Lambda  } _{ eq }^{ \infty  }\left( { Ba }{ Cl } _{ 2 } \right) ={ \Lambda  } _{ eq }^{ \infty  }\left( { Ba }^{ 2+ } \right) +2{ \Lambda  } _{ eq }^{ \infty  }\left( { Cl }^{ - } \right) \ \qquad \qquad \quad =127+76\times 2\ \qquad \qquad \quad =279{ \Omega  }^{ -1 }{ cm }^{ -1 }{ eq }^{ -1 }$

When sodium lauryl sulphate is dissolved in water in an appreciable amount, micelle formation takes place. Which of the following options is correct regarding the formation process?

  1. Micelle formation can occur at any temperature

  2. At substantially lower concentrations as concentration increases, conductivity should decrease.

  3. On dilution micelle molar conductance should decrease.

  4. The micelle formation in given case will lead to formation in given case will lead to formation of positively charged colloid.


Correct Option: B
Explanation:

At substantially lower concentrations as concentration increases , conductivity increases. Micelle formation can occur at above critical micelle concentration which is at 25$^0$C for sodium lauryl sulphate. It doesnt form a positively charged colloid .

The charge required for reducing $1$ mole of $MnO^- _4$ to $Mn^{2+}$ is:

  1. $1.93\times 10^5$C

  2. $2.895\times 10^5$C

  3. $4.28\times 10^5$C

  4. $4.825\times 10^5$C


Correct Option: D
Explanation:
We will write the reactions and do molar analysis to get clear idea of  the solution.
In the following reaction the oxidation state of Mn is changing from +7 to +2.
$MnO^{-} _{4}+5e^{-}\rightarrow Mn^{2+}$
Here, 5 moles of electrons are needed for reduction of 1 mole of $MnO^{-} _4$ to $ Mn^{2+}$
As, 5 moles of elctrons=5 Faradays
$\implies$Quantity of charge required $=5\times96500=4.825\times10^{5} $ Coulombs

Fill in the blank with appropriate words.
The electrolytic solution is always neutral because the total charge on $\underline{(i)}$ is equal to $\underline{(ii)}$ on $\underline{(iii)}$. Unlike the metallic conductor, the electrolyte conducts the electric current by virtue of movement of its $\underline{(iv)}$. The property due to which a metal tends to go into solution in term of positive ions is known as $\underline{(v)}$.
(i), (ii), (iii), (iv) and (v) respectively are:

  1. cations, partial charge, anions, electrons, reduction

  2. cations, total charge, anions, ions, oxidation

  3. cations, ionic charge, anions, atoms, dissolution

  4. cations, partial charge, anions, molecules, electrolysis


Correct Option: B
Explanation:

To maintain neutrality, the total charge on cation is equal to the total charge on anion.

Metallic conductor contains ions. Hence, the current is due to the movement of ions.
Oxidation is the loss of an electron. 
Hence, metals undergo oxidation.
$M\longrightarrow M^{2+}+2e^-$

If equivalent conductance of 1M benzoic acid is $12.8\ { ohm }^{ -1 }{ cm }^{ 2 }$ and if the conductance of benzoate ion and ${ H }^{ -1 }$ ion are 42 and $288.42\ { ohm }^{ -1 }{ cm }^{ 2 }$ respectively. Its degree of dissolution is:

  1. 39%

  2. 3.9%

  3. 0.35%

  4. 0.039%


Correct Option: B
Explanation:

$\Lambda ^{ 0 } _{ m\left( C _{ 6 }H _{ 5 }COOH \right)  }={ \Lambda  } _{ (C _{ 6 }{ H } _{ 5 }CO{ O }^{ - }) }^{ 0 }\quad +{ \Lambda  }^{ 0 } _{ \left( { H }^{ + } \right)  }$ 

$\ \quad \quad \quad \quad \quad \quad \quad \quad =42+288.42=330.42\ now\quad we\quad have,\ \alpha =\frac { { \Lambda  } _{ m }^{ c } }{ { \Lambda  } _{ m }^{ 0 } } =\frac { 12.8 }{ 330.42 } =3.9$

Which of the following decreases on dilution of electrolyte solution?

  1. Equivalent conductance

  2. Molar conductance

  3. Specific conductance

  4. Conductance


Correct Option: B
Explanation:

Conductance $=\cfrac{kA}{l}$ 

where, $k$ is conductivity
$k=K\times G$
where, $K$ is cell constant
Does not depend on volume of the solution but molar conductance.
$\wedge _m=\cfrac{K}{C}$
$C$ is concentration which depends on volume. Hence, affected by dilution.

With rise in temperature, electrolytic conductance :

  1. increases

  2. decreases

  3. disappear

  4. none of the above


Correct Option: A
Explanation:

Generally the conductivity of a solution increases with temperature, as the mobility of the ions increases.
Conductivity
(or specific conductance) of an electrolyte solution is a measure of its ability to conduct electricity.
Electrolytic conductance generally increases with rise in temperature.

Conductivity of metal decreases with temperature while conductivity of electrolytic conductors  :

  1. increases with temperature

  2. slightly decreases with temperature

  3. remains same

  4. slightly increases with temperature


Correct Option: A
Explanation:

In metals, conductivity is due to movement of free electrons. When temperature increases, the vibration of metal ions increases. This results in increase in resistance of metal and hence, decrease in conductivity. In electrolytic conductors, the ions are charge carriers and with increase in temperature, ionization increases and hence, conductivity increases.

On increasing temperature, the conduction in metallic conductors :

  1. increases

  2. decreases

  3. remains constant

  4. none of the above


Correct Option: B
Explanation:

Increasing the temperature will inhibit conduction in a metallic conductors because the increased thermal motions of the electrons will tend to interfere with their regular flow in an electric current.

The molar conductivity of cation and anion of salt $BA$ are $180$ and $220\ mhos\ cm^{2} mol^{-2}$ respectively. The molar conductivity of $BA$ at infinite dilution is:

  1. $90\ mhos \ cm^{2} mol^{-1}$

  2. $110\ mhos \ cm^{2} mol^{-1}$

  3. $400\ mhos \ cm^{2} mol^{-1}$

  4. $200\ mhos \ cm^{2} mol^{-1}$


Correct Option: C

A solution containing one mole per litre of each $Cu(NO _3) _2$, $AgNO _3, Hg _2(NO _3) _2$ and $Mg(NO _3) _2$ is being electrolysed by using inert electrodes. The values of standard electrode potentials in volts(reduction potential) are.
$Ag^+/Ag=+0.80, Hg^{2+} _2/2Hg =+0.79$
$Cu^{2+}/Cu=+0.34, Mg^{2+}/Mg =-2.37$
With increasing voltage, the sequence of deposition of metals on the cathode will be:

  1. Ag, Hg, Cu, Mg

  2. Mg, Cu, Hg, Ag

  3. Ag, Hg, Cu

  4. Cu, Hg, Ag


Correct Option: C

 The standard electrode potentials ${\text{E}} _{{{\text{I}} _2}/{1^ - }}^ \circ ,{\text{E}} _{{\text{B}}{{\text{r}}^ - }/{\text{B}}{{\text{r}} _2}}^ \circ $ and ${\text{E}} _{{\text{Fe/F}}{{\text{e}}^{2 + }}}^ \circ $ are respectively $ + 0.54{\text{V,}} - 1.09{\text{V}}$ and 0.44 V. On the basis of the above data which of the following process is nonspontaneous?

  1. ${\text{B}}{{\text{r}} _2} + 2{{\text{I}}^ - }\;{\text{2B}}{{\text{r}}^ - } + {{\text{I}} _2}{\text{ }}$

  2. ${\text{Fe}} + {\text{B}}{{\text{r}} _2}\;{\text{F}}{{\text{e}}^{2 + }} + 2{\text{B}}{{\text{r}}^ - }$

  3. ${\text{Fe}} + {{\text{I}} _2}{\text{ F}}{{\text{e}}^{2 + }} + 2{{\text{I}}^ - }$

  4. ${{\text{I}} _2} + 2{\text{B}}{{\text{r}}^ - }2{{\text{I}}^ - } + {\text{B}}{{\text{r}} _2}$


Correct Option: D
Explanation:

the one which is having higher oxidation potential will undergo oxidation,

in D, $I^-$ is having lower reduction potential in comparison to $Br^-$, so has to undergo oxidation but in option D, it is getting oxidized.
hence, it is a nonspontaneous reaction.

An alkali which dissociates partially on passage of an electric current is:

  1. sodium hydroxide

  2. nickel metal

  3. ammonium hydroxide

  4. copper


Correct Option: C
Explanation:

We have,

Sodium chloride is an ionic compound which is already present in the ionic form and completely dissociated on the passage of electric current,
Nickel and copper metal have higher reduction potential so, reduction takes place on passage of electric current,
ammonium hydroxide is a weak base it is partially dissociated on the passage of electric current. 

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