Tag: electrochemistry

Questions Related to electrochemistry

Multiple choice conductivity and its types electrochemistry

Equivalent conductance of $BaCl _2, H _2SO _4$ and $HCl$ are $x _1, x _2$ and $x _3 S cm^2 equiv^{-1}$ at infinite dilution.If specific conductance of saturated $BaSO _4$ solution is of $y S cm^1$ then $K _{sp}$ of $BaSO _4$ is:

  1. $\frac{10^3y}{2(x _1 + x _2 - 2x _3)}$
  2. $\frac{10^6y^2}{4(x _1 + x _2 - 2x _3)^2}$
  3. $\frac{10^6y^2}{2(x _1 + x _2 - x _3)^2}$
  4. $\frac{x _1 + x _2 - 2x _3}{10^6y^2}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

${ \Lambda  } _{ eq }\quad (Ba{ SO } _{ 4 })={ \Lambda  } _{ eq }\left( Ba{ Cl } _{ 2 } \right) +{ \Lambda  } _{ eq }\left( { H } _{ 2 }{ SO } _{ 4 } \right) -2{ \Lambda  } _{ eq }\left( HCl \right) $

                            $=\left( { x } _{ 1 }+{ x } _{ 2 }-{ 2x } _{ 3 } \right) S{ cm }^{ 2 }{ eq }^{ -1 }$
$\because { \Lambda  } _{ eq }=K\times \cfrac { 1000 }{ N } \quad \Rightarrow \quad N=\left( \cfrac { y\times { 10 }^{ 3 } }{ { x } _{ 1 }+{ x } _{ 2 }-{ 2x } _{ 3 } }  \right) \quad \left( \because { n } _{ f }=2 \right) $
$\therefore \quad M=\left{ \cfrac { y\times { 10 }^{ 3 } }{ 2\left( { x } _{ 1 }+{ x } _{ 2 }-{ 2x } _{ 3 } \right)  }  \right} $
$\therefore \quad { K } _{ sp }={ \left( M \right)  }^{ 2 }=\left{ \cfrac { { y }^{ 2 }\times { 10 }^{ 6 } }{ 4{ \left( { x } _{ 1 }+{ x } _{ 2 }-{ 2x } _{ 3 } \right)  }^{ 2 } }  \right} $

Multiple choice conductivity and its types electrochemistry

For $HCl$ solution at ${25}^{o}C$ equivalent conductance at infinite dilution is $425 \ {ohm}^{-1}{cm}^{2}{equiv}^{-1}$. The specific conductance of a solution of $HCl$ is $3.825$ ${ohm}^{-1}{cm}^{-1}$. If the apparent degree of dissociation is $90$% the normality of the solution is :

  1. $0.90N$
  2. $1.0N$
  3. $10\ N$
  4. $1.2N$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The degree of dissociation alpha = Lambda_m / Lambda_m_infinity. Given alpha = 0.9, Lambda_m_infinity = 425, and specific conductance kappa = 3.825. Lambda_m = kappa * 1000 / M. Solving for M (molarity/normality for HCl) gives 10 N.

Multiple choice conductivity and its types electrochemistry

The equivalent conductivity of $0.1 N \ CHNCH _{3}COOH$ at $25^{0}C$ is 80 and at infinite dilution it is 400, the degree of dissociation of $CH _{3}COOH$ is :

  1. 1

  2. 0.2

  3. 0.1

  4. 0.5

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

Given:-

$\wedge _{eq}(CH _3COOH)= 80 S cm^{-2} eq^{-1}$

$\wedge^{\infty} _{eq}(CH _3COOH)$ at infinite dilution= $400S cm^2 eq^{-1}$

$\alpha \longrightarrow$ Degree of dissociation

$\alpha= \cfrac {\wedge^m _{eq}}{\wedge^{\infty} _{eq}}=\cfrac {80}{400}= 0.2$

$\alpha= 0.2$

Multiple choice conductivity and its types electrochemistry

In infinite dilusions, the equivalent conductances of $Ba^{2+}$ and $Cl^{-}$ are $127$ and $76 ohm^{-1} \, cm^{-1} \, eqvt^{-1}$. The equivalent conductivity of $BaCl _2$ at indefinite dilution is?

  1. $101.5$
  2. $203.5$
  3. $139.5$
  4. $279.5$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The equivalent conductance of BaCl2 at infinite dilution, 


λ of BaCl2=1/2 λ of Ba2+ + λof Cl
       

 =127/2+76 

=139.

Option C is correct answer

Multiple choice conductivity and its types electrochemistry

${\text{N}}{{\text{a}} _{\text{3}}}{\text{Al}}{{\text{F}} _{\text{6}}}\,\,$ is added to $\,{\text{A}}{{\text{l}} _{\text{2}}}{{\text{O}} _{\text{3}}}$

  1. Improve the electrical conductivity of the cell

  2. Increases rate of production

  3. Increases the melting point

  4. Decrease the electrical conductivity

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

Cryolite (Na3AlF6) is added to alumina (Al2O3) in the Hall-Heroult process primarily to lower the melting point of the mixture and improve electrical conductivity.

Multiple choice conductivity and its types electrochemistry

The equivalent conductance of $0.02$ M acctic acid  $1.62.*{10^{ - 3}}$.  Degree of ironisation $'a'$ of $C{H _3}COOH$ is:
$({x _H} = 349.83oh{m^{ - 1}}and\lambda C{H _3}CO{O^ - } = 40.89ohm{s^{ - 1}}$

  1. $0.01$
  2. $0.02$
  3. $0.03$
  4. $0.04$
Reveal answer Fill a bubble to check yourself
B Correct answer
Multiple choice conductivity and its types electrochemistry

Equivalent conductivity of $BaCl _2,H _2SO _4$ and HCI, are $x _1,x _2$ and $x _3scm^{-1}eq^{-1}$ at infinite dilution. If conductivity of saturated $BaSO _4$ solution is x $Scm^{-1}$, then $K _{sp}$ of $BaSO _4$ is

  1. $\dfrac {500x} {(x _1+x _2-2x _3)}$
  2. $\dfrac {10^6x^2} {(x _1+x _2-2x _3)^3}$
  3. $\dfrac {2.5\times10^5 x^2} {x _1-2x _2-x _3)^2}$
  4. $\dfrac {0.25 x^2} {x _1 + x _2-x _3)^2}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice conductivity and its types electrochemistry

Molar conductance of $C{a^{2 + }}$ and $C{l^ - }$ are  $120\,c{m^2}\,$ $mo{l^{ - 1}}$ and $77\,S\,c{m^2}\,mo{l^{ - 1}}$ respectively. What is the equivalent conductance of $CaC{l _2}$ ?

  1. $98.5\,Sc{m^2}e{q^{ - 1}}$
  2. $137\,Sc{m^2}e{q^{ - 1}}$
  3. $197\,Sc{m^2}e{q^{ - 1}}$
  4. $247\,Sc{m^2}e{q^{ - 1}}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Equivalent conductance is calculated by dividing the molar conductance by the valence factor of the electrolyte. For calcium chloride, the valence factor is 2, and applying Kohlrausch law using the given ionic conductances gives 120 plus two times 77, all divided by 2, which equals 137.

Multiple choice conductivity and its types electrochemistry

At infinite dilution equivalent conductance of ${B^{ + 2}}$ & CI ions are 127  &  76$oh{m^{ - 1}}$ $c{m^{ - 1}}$` $e{q^{ - 1}}$ respectively. Equivalent conductance  of $BaC{I _2}$ at infinite diluition is : 

  1. 139.5

  2. 101.5

  3. 203

  4. 279

Reveal answer Fill a bubble to check yourself
C Correct answer
Multiple choice conductivity and its types electrochemistry

Equivalent constant of standard $BaSO _{4}$ is $400ohm^{-1}\ cm^{2}$ equiv$^{-1}$ and specific conduction is $8\times 10^{-5}\ ohm^{-1}\ cn^{-1}$. Hence $K _{SP}$ of $BaSO _{4}$ is

  1. $4\times 10^{-8}M^{2}$
  2. $1\times 10^{-8}M^{2}$
  3. $2\times 10^{-4}M^{2}$
  4. $1\times 10^{-4}M^{2}$
Reveal answer Fill a bubble to check yourself
B Correct answer