Which cell will measure standard electrode potential of copper electrode?
Electrode potential for Mg electrode varies according to the equation $\mathrm{E}_{\mathrm{Mg}^{2+} / \mathrm{Mg}}=\mathrm{E}_{\mathrm{Mg}^{2+} / \mathrm{Mg}}^{\mathrm{s}}-\frac{0.059}{2} \log \frac{1}{\left[\mathrm{Mg}^{2+}\right]}$. The graph of $\mathrm{E}_{\mathrm{Mg}^{2+} / \mathrm{Mg}}$ vs $\log \left[\mathrm{Mg}^{2+}\right]$ is
Which of the following statement is correct?
The difference between the electrode potentials of two electrodes when no current is drawn through the cell is called ............ .
Which of the following statement is not correct about an inert electrode in a cell?
An electrochemical cell can behave like an electrolytic cell when ........... .
Which of the statements about solutions of electrolytes is not correct?
Using the data given below find out the strongest reducing agent.
$$\begin{aligned} & \mathrm{E}^{\mathrm{S} \mathrm{Cr}_2 \mathrm{O}^{2-} / \mathrm{Cr}^{3+}} 1.33 \mathrm{~V} ; \quad \mathrm{E}^{\mathrm{s}} \mathrm{Cl}_2 / \mathrm{Cl}^{-}=1.36 \mathrm{~V} \\ & \mathrm{E}^{\mathrm{S}} \mathrm{MnO}_4^{-} / \mathrm{Mr}^{2+}=1.51 \mathrm{~V} ; \mathrm{E}^{\mathrm{s}} \mathrm{Cr}^{3+} / \mathrm{Cr}=-0.74 \mathrm{~V} \end{aligned}$$
Use the data given in Q. 8 and find out which of the following is the strongest oxidising agent?
Using the data given in 0.8 find out in which option the order of reducing power is correct.
Use the data given in Q. 8 and find out the most stable ion in its reduced form.
Use the data of $Q .8$ and find out the most stable oxidised species.
The quantity of charge required to obtain one mole of aluminium from $\mathrm{Al}_2 \mathrm{O}_3$ is ............. .
The cell constant of a conductivity cell ............ .
While charging the lead storage battery ............ .
$\Lambda_{\mathrm{m}\left(\mathrm{NH}_4 \mathrm{OH}\right)}^{\circ}$ is equal to ................ .
In the electrolysis of aqueous sodium chloride solution which of the half cell reaction will occur at anode?
Assertion (A) Cu is less reactive than hydrogen.
Reason $(R) \mathrm{E}_{\mathrm{Cu}^{2+} / \mathrm{Cu}}^{\mathrm{S}}$ is negative.
Assertion (A) $\mathrm{E}_{\text {cell }}$ should have a positive value for the cell to function.
Reason (R) $\mathrm{E}_{\text {cathode }}<\mathrm{E}_{\text {anode }}$
Assertion (A) Conductivity of all electrolytes decreases on dilution.
Reason (R) On dilution number of ions per unit volume decreases.
Assertion (A) $\Lambda_m$ for weak electrolytes shows a sharp increase when the electrolytic solution is diluted.
Reason (R) For weak electrolytes degree of dissociation increases with dilution of solution.
Assertion (A) Mercury cell does not give steady potential.
Reason (R) In the cell reaction, ions are not involved in solution.
Assertion (A) Electrolysis of NaCl solution gives chlorine at anode instead of $\mathrm{O}_2$.
Reason $(R)$ Formation of oxygen at anode requires over voltage.
Assertion (A) For measuring resistance of an ionic solution an AC source is used.
Reason (R) Concentration of ionic solution will change if DC source is used.
Assertion (A) Current stops flowing when $\mathrm{E}_{\text {cell }}=0$.
Reason (R) Equilibrium of the cell reaction is attained.
Assertion (A) $\mathrm{E}_{\mathrm{Ag}^{+} / \mathrm{Ag}}$ increase with increase in concentration of $\mathrm{Ag}^{+}$ ions.
Reason $(R) \mathrm{E}_{\mathrm{Ag}^{+} / \mathrm{Ag}}$ has a positive value.
Assertion (A) Copper sulphate can be stored in zinc vessel.
Reason (R) Zinc is less reactive than copper.
The positive value of the standard electrode potential of $\mathrm{Cu}^{2+} / \mathrm{Cu}$ indicates that ............ .
$\mathrm{E}_{\text {cell }}^{\mathrm{s}}$ for some half cell reactions are given below. On the basis of these mark the correct answer.
(a) $\mathrm{H}^{+}(\mathrm{aq})+\mathrm{e}^{-} \longrightarrow \frac{1}{2} \mathrm{H}_2(\mathrm{~g})\qquad; \mathrm{E}_{\text {cell }}^{\mathrm{s}}=0.00 \mathrm{~V}$
(b) $2 \mathrm{H}_2 \mathrm{O}(\mathrm{l}) \longrightarrow \mathrm{O}_2(\mathrm{~g})+4 \mathrm{H}^{+}(\mathrm{aq})+4 \mathrm{e}^{-}\qquad$; $\mathrm{E}_{\text {cell }}^{\mathrm{s}}=1.23 \mathrm{~V}$
(c) $2 \mathrm{SO}_4^{2-}(\mathrm{aq}) \longrightarrow \mathrm{S}_2 \mathrm{O}_8^{2-}(\mathrm{aq})+2 \mathrm{e}^{-} ; \quad \mathrm{E}_{\text {cell }}^{\mathrm{s}}=1.96 \mathrm{~V}$
$\mathrm{E}_{\text {cell }}^{\circ}=1.1 \mathrm{~V}$ or Daniel cell. Which of the following expressions are correct description of state of equilibrium in this cell?
Conductivity of an electrolytic solution depends on
$\Lambda_{\mathrm{m}}^{\circ} \mathrm{H}_2 \mathrm{O}$ is equal to. ............... .
What will happen during the electrolysis of aqueous solution of $\mathrm{CuSO}_4$ by using platinum electrodes?
What will happen during the electrolysis of aqueous solution of $\mathrm{CuSO}_4$ in the presence of Cu electrodes?
Conductivity $\kappa$, is equal to ............. .
Molar conductivity of ionic solution depends on ........... .
For the given cell, $\mathrm{Mg}\left|\mathrm{Mg}^{2+} \| \mathrm{Cu}^{2+}\right| \mathrm{Cu}$
Can absolute electrode potential of an electrode be measured?
Can $E_{\text {cell }}^{\circ}$ or $\Delta_{\mathrm{r}} \mathrm{G}^{\circ}$ for cell reaction ever be equal to zero ?
Under what condition is $E_{\text {cell }}=0$ or $\Delta_r G=0$ ?
What does the negative sign in the expression $E^{\mathrm{s}} \mathrm{Zn}^{2+} / \mathrm{Zn}=-0.76 \mathrm{~V}$ mean?
Aqueous copper sulphate solution and aqueous silver nitrate solution are electrolysed by 1 ampere current for 10 minutes in separate electrolytic cells. Will the mass of copper and silver deposited on the cathode be same or different? Explain your answer.
Depict the galvanic cell in which the cell reaction is
$$\mathrm{Cu}+2 \mathrm{Ag}^{+} \longrightarrow 2 \mathrm{Ag}+\mathrm{Cu}^{2+}$$
Value of standard electrode potential for the oxidation of $\mathrm{Cl}^{-}$ions is more positive than that of water, even then in the electrolysis of aqueous sodium chloride, why is $\mathrm{Cl}^{-}$oxidised at anode instead of water?
What is electrode potential?
Consider the following diagram in which an electrochemical cell is coupled to an electrolytic cell. What will be the polarity of electrodes 'A' and ' B ' in the electrolytic cell?
Why is alternating current used for measuring resistance of an electrolytic solution?
A galvanic cell has electrical potential of 1.1V. If an opposing potential of 1.1 V is applied to this cell, what will happen to the cell reaction and current flowing through the cell ?
How will the pH of brine (aq NaCl solution) be affected when it is electrolysed?
Unlike dry cell, the mercury cell has a constant cell potential throughout its useful life. Why ?
Solutions of two electrolytes $A$ and $B$ are diluted. The $\Lambda_m$ of ' $B$ ' increases 1.5 times while that of $A$ increases 25 times. Which of the two is a strong electrolyte ? Justify your answer.
When acidulated water (dil. $\mathrm{H}_2 \mathrm{SO}_4$ solution) is electrolysed, with pH of the solution be affected ? Justify your answer.
In an aqueous solution how does specific conductivity of electrolytes change with addition of water?
Which reference electrode is used to measure the electrode potential of other electrodes?
Consider a cell given below
$$\mathrm{Cu}\left|\mathrm{Cu}^{2+}\right|\left|\mathrm{Cl}^{-}\right| \mathrm{Cl}_{2,}, \mathrm{Pt}$$
Write the reactions that occur at anode and cathode.
Write the Nernst equation for the cell reaction in the Daniel cell. How will the $E_{\text {cell }}$ be affected when concentration of $\mathrm{Zn}^{2+}$ ions is increased?
What advantage do the fuel cells have over primary and secondary batteries ?
Write the cell reaction of a lead storage battery when it is discharged. How does the density of the electrolyte change when the battery is discharged?
Why on dilution the $\Lambda_{\mathrm{m}}$ of $\mathrm{CH}_3 \mathrm{COOH}$ increases drastically, while that of $\mathrm{CH}_3 \mathrm{COONa}$ increases gradually?
Match the terms given in Column I with the units given in Column II.
| Column I | Column II | ||
|---|---|---|---|
| A. | $\wedge_m$ | 1. | S cm$^{-1}$ |
| B. | $E_{\text{cell}}$ | 2. | m$^{-1}$ |
| C. | $\kappa$ | 3. | S cm$^2$ mol$^{-1}$ |
| D. | $G^*$ | 4. | V |
Match the terms given in Column I with the items given in Column II.
| Column I | Column II | ||
|---|---|---|---|
| A. | $\wedge_m$ | 1. | Intensive property |
| B. | $E^s_{\text{cell}}$ | 2. | Depends on number of ions/volume |
| C. | $\kappa$ | 3. | Extensive property |
| D. | $\Delta_r G_{\text{cell}}$ | 4. | Increases with dilution |
Match the items of Column I and Column II.
| Column I | Column II | ||
|---|---|---|---|
| A. | Lead storage battery | 1. | Maximum efficiency |
| B. | Mercury cell | 2. | Prevented by galvanisation |
| C. | Fuel cell | 3. | Gives steady potential |
| D. | Rusting | 4. | Pb is anode, PbO$_2$ is cathode |
Match the items of Column I and Column II.
| Column I | Column II | ||
|---|---|---|---|
| A. | $\kappa$ | 1. | $I \times t$ |
| B. | $\wedge_m$ | 2. | $\wedge_m / \wedge^o_m$ |
| C. | $\alpha$ | 3. | $\frac{\kappa}{C}$ |
| D. | $Q$ | 4. | $\frac{G^*}{R}$ |
Match the items of Column I and Column II.
| Column I | Column II | ||
|---|---|---|---|
| A. | Lechlanche cell | 1. | Cell reaction $2 \mathrm{H}_2+\mathrm{O}_2 \longrightarrow 2 \mathrm{H}_2 \mathrm{O}$ |
| B. | Ni-Cd cell | 2. | Does not involve any ion in solution and is used in hearing aids. |
| C. | Fuel cell | 3. | Rechargeable |
| D. | Mercury cell | 4. | Reaction at anode, $\mathrm{Zn} \longrightarrow \mathrm{Zn}^{2+}+2 e^{-}$ |
| 5. | Converts energy of combustion into electrical energy |
Match the items of Column I and Column II on the basis of data given below
$$\begin{aligned} \mathrm{E}_{\mathrm{F}_2 / \mathrm{F}^{-}}^{\mathrm{s}} & =2.87 \mathrm{~V}, \mathrm{E}_{\mathrm{Li}^{+} / \mathrm{Li}}^{\mathrm{s}}=-3.5 \mathrm{~V}, \\ \mathrm{E}_{\mathrm{Au}^{3+} / \mathrm{Au}} & =1.4 \mathrm{~V}, \mathrm{E}_{\mathrm{Br}_2 / \mathrm{Br}^{-}}^{\mathrm{s}}=1.09 \mathrm{~V} \end{aligned}$$
| Column I | Column II | ||
|---|---|---|---|
| A. | F$_2$ | 1. | Metal is the strongest reducing agent |
| B. | Li | 2. | Metal ion which is the weakest oxidising agent |
| C. | Au$^{3+}$ | 3. | Non-metal which is the best oxidising agent |
| D. | Br$^{-}$ | 4. | Unreactive metal |
| E. | Au | 5. | Anion that can be oxidised by Au$^{3+}$ |
| F. | Li$^{+}$ | 6. | Anion which is the weakest reducing agent |
| G. | F$^-$ | 7. | Metal ion which is an oxidising agent |
Consider the figure and answer the following questions.
(i) Cell ' $A$ ' has $\mathrm{E}_{\text {cell }}=2 \mathrm{~V}$ and Cell ' B ' has $\mathrm{E}_{\text {cell }}=1.1 \mathrm{~V}$ which of the two cells 'A' or 'B' will act as an electrolytic cell. Which electrode reactions will occur in this cell?
(ii) If cell ' $A$ ' has $\mathrm{E}_{\text {cell }}=0.5 \mathrm{~V}$ and cell ' $B^{\prime}$ has $\mathrm{E}_{\text {cell }}=1.1 \mathrm{~V}$ then what will be the reactions at anode and cathode?
Consider figure from the above question and answer the questions (i) to (vi) given below.
(i) Redraw the diagram to show the direction of electron flow.
(ii) Is silver plate the anode or cathode?
(iii) What will happen if salt bridge is removed?
(iv) When will the cell stop functioning?
(v) How will concentration of $\mathrm{Zn}^{2+}$ ions and $\mathrm{Ag}^{+}$ions be affected when the cell functions?
(vi) How will the concentration of $\mathrm{Zn}^{2+}$ ions and $\mathrm{Ag}^{+}$ ions be affected after the cell becomes 'dead'?
What is the relationship between Gibbs free energy of the cell reaction in a galvanic cell and the emf of the cell? When will the maximum work be obtained from a galvanic cell?