Get Answers to all your Questions

header-bg qa

For which cell emf is independent of the concentrations of electrolytes used?

  • Option 1)

    Fe\left | FeO(s) \right |KOH(aq) |NiO(s)|Ni_2O_3(s) |Ni

  • Option 2)

    Pt(H_2)|HCl|Pt(Cl)_2

  • Option 3)

    Zn|Zn(NO_3)||CuSO_4|Cu

  • Option 4)

    Hg_1HgCl_2|KCl ||AgNO_3|Ag

 

Answers (1)

As we learnt in 

Electrode Potential(Nerst Equation) -

M^{n+}(aq)+ne^{-}\rightarrow M(s)

- wherein

E_{(M^{n+}/M)}=E_{(M^{n+}/M)}^{0}-\frac{RT}{nf}ln\frac{[M]}{[M^{n+}]}

[M^{n+}] is concentration of species

F= 96487 C moi^{-1}

R= 8.314 JK^{-1}moi^{-1}

T= Temperature in kelvin

 

Lets write down the reactions of anode and cathode .

At anode  Fe\left ( s \right )+2OH^{-}\rightarrow EeO.H_{2}+2e^{-}

At cathode, Ni_{2}O_{3}\left ( s \right )+H_{2}O+ 2e^{-}\rightarrow 2NiO+2O H^{-}

E_{cell}=E_{C}-E_{A}=E_{Ni_{2}O_{3}/NiO}-\frac{0.059}{2}\, \, log\, \, \frac{\left [ OH^{-} \right ]}{\left [ OH^{-} \right ]}

\therefore Soution is 1


Option 1)

Fe\left | FeO(s) \right |KOH(aq) |NiO(s)|Ni_2O_3(s) |Ni

Correct

Option 2)

Pt(H_2)|HCl|Pt(Cl)_2

Incorrect

Option 3)

Zn|Zn(NO_3)||CuSO_4|Cu

Incorrect

Option 4)

Hg_1HgCl_2|KCl ||AgNO_3|Ag

Incorrect

Posted by

Vakul

View full answer