Tag: metallic and electrolytic conduction

Questions Related to metallic and electrolytic conduction

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:

metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

  1. $1 : 2 : 3$

  2. $2 : 3 : 1$

  3. $6 : 3 : 2$

  4. $3 : 4 : 2$

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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 ?

metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

  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

Show answer
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:

metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

  1. $139.5$

  2. $101.5$

  3. $203$

  4. $279$

Show answer
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?

metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

  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.

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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:

metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

  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

Show answer
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:

metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

  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

Show answer
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:

metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

  1. 39%

  2. 3.9%

  3. 0.35%

  4. 0.039%

Show answer
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?

metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

  1. Equivalent conductance

  2. Molar conductance

  3. Specific conductance

  4. Conductance

Show answer
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 :

metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

  1. increases

  2. decreases

  3. disappear

  4. none of the above

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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  :

metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

  1. increases with temperature

  2. slightly decreases with temperature

  3. remains same

  4. slightly increases with temperature

Show answer
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.