Tag: electrolysis

Quizzes (4) Questions (120)

Questions Related to electrolysis

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

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
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

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 $KCl$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Standard KCl solutions (like 0.1M or 0.01M) are used for cell constant determination because their conductivity is accurately known. Saturated KCl is not used because its concentration and conductivity can be unstable or difficult to reproduce precisely.

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

Metallic conduction involves:

  1. no chemical change

  2. flow of electrons

  3. transfer of matter

  4. conductance decreases with increase in temperature
Reveal answer Fill a bubble to check yourself
B,D Correct answer
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 $D$

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

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
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

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

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

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 } $
Reveal answer Fill a bubble to check yourself
A Correct answer
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 $=2x+\cfrac { y }{ 2 }$

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

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. $3 : 4 : 2$
Reveal answer Fill a bubble to check yourself
C Correct answer
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$=6:3:2$.

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

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
Reveal answer Fill a bubble to check yourself
C Correct answer
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. 

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

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. $279$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

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

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

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.
Reveal answer Fill a bubble to check yourself
B Correct answer
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 .

Multiple choice metallic and electrolytic conduction electrolysis chemical reactions electrochemistry chemistry

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
Reveal answer Fill a bubble to check yourself
D Correct answer
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