List of top Chemistry Questions on Nernst Equation asked in CBSE CLASS XII

Calculate the electrode potential of a half-cell for zinc electrode dipping in \(0.01\,M\) \(ZnSO_4\) solution at \(25^\circ C\). \[ \text{Given : } E^\circ_{Zn^{2+}/Zn}=-0.76\,V \] \[ \log 10 = 1 \]
Calculate emf of the following cell at \(298\,K\) : \[ Cr(s)\,|\,Cr^{3+}(aq,\;0.1\,M)\,||\,Fe^{2+}(aq,\;0.01\,M)\,|\,Fe(s) \] (Given : \[ E^\circ_{Cr^{3+}/Cr}=-0.74\,V, \] \[ E^\circ_{Fe^{2+}/Fe}=-0.44\,V, \] \[ \log 10 = 1 \] )
Answer the following: \[ (a)(i)\;\text{Calculate the electrode potential of a half-cell for zinc electrode dipping in }0.01M\;ZnSO_4\text{ solution at }25^\circ C. \] \[ E^\circ_{Zn^{2+}/Zn}=-0.76V,\quad \log 10=1 \] \[ (a)(ii)\;\text{Write anode, cathode and overall reaction involved in dry cell.} \] \[ (a)(iii)\;\text{Equilibrium constant }(K_c)\text{ is related to }E^\circ_{\text{cell}},\text{ but not to }E_{\text{cell}}.\text{ Why?} \]
Calculate emf and ΔG for the following cell at 298 K:
Mg(s) | Mg2+(0.01 M) || Ag+(0.001 M) | Ag(s)
Given: E°Mg2+/Mg = -2.37 V, E°Ag+/Ag = +0.80 V. [1 F = 96500 C mol-1, log 10 = 1]
For the reaction:
2 AgCl(s) + H2(g) (0.4 atm) → 2 Ag(s) + 2 H+(0.1 M) + 2 Cl-(0.2 M)
Calculate the emf of the cell at 25 °C.
Given: ΔG° = -43500 J mol-1. [log 10 = 1, 1 F = 96500 C mol-1]
Answer the following:

(i) Why is the Equilibrium Constant \(K_c\) related to \(E^\circ_{cell}\) and not to \(E_{cell}\)?

(ii) Two metals 'A' and 'B' have standard electrode potential values of \(-0.24\) V and \(+0.80\) V respectively. Which of these will liberate hydrogen gas from dil. \(H_2SO_4\)?

(iii) Write the cell reaction which occurs in lead storage battery when it is in charging.
Calculate the electrode potential of a half-cell for a zinc electrode dipping in 0·01 M $\mathrm{ZnSO_4}$ solution at 25°C. [Given : $\mathrm{E^\circ_{Zn^{2+}/Zn} = -0.76\,V}$, log 10 = 1]
Equilibrium constant $\mathrm{(K_c)}$ is related to $\mathrm{E^\circ_{cell}}$, but not to $\mathrm{E_{cell}}$. Why ?
The resistance of a conductivity cell containing 0.001 M KCl solution at 298 K is 1000 ohm. What is the cell constant if conductivity of 0.001 M KCl solution at 298 K is 0.125 × 10−3 S cm−1?