Nernst Equation

Q. Which is a stronger reducing agent Cr²⁺ or Fe²⁺ and why?

Q.

Write the Nernst equation and emf of the following cells at 298 K:

(i) $Mg\left(s\right)|M{g}^{2+}\left(0.001M\right)||C{u}^{2+}\left(0.001M\right)|Cu\left(s\right)$

(ii) $Fe\left(s\right)|F{e}^{2+}\left(0.001M\right)||H^{+}\left(1M\right)|H_2\left(g\right)\left(1bar\right)|Pt\left(s\right)$

(iii) $Sn\left(s\right)|S{n}^{2+}\left(0.050M\right)||H^{+}\left(0.020M\right)|H_2\left(g\right)\left(1bar\right)|Pt\left(s\right)$

(iv) $Pt\left(s\right)|B{r}_2\left(l\right)|B{r}^{-}\left(0.010M\right)||H^{+}\left(0.030M\right)|H_2\left(g\right)\left(1bar|Pt\right(s\left)\right)$

$E_{\left(\frac{M{g}^{2+}}{Mg}\right)}^{\circ }=-2.37V;E_{\left(\frac{C{u}^{2+}}{Cu}\right)}^{\circ }=+0.34V;E_{\left(\frac{F{e}^{2+}}{Fe}\right)}^{\circ }=-0.44V;E_{\left(\frac{S{n}^{2+}}{Sn}\right)}^{\circ }=-0.14V;E_{\left(\frac{\frac{1}{B{r}_2}}{B{r}^{-}}\right)}^{\circ }=+1.08V,$

Q.

Calcium hydroxide reacts with ammonium chloride to give ammonia, according to the following equation:

$\mathrm{Ca}{\left(\mathrm{OH}\right)}_2+2{\mathrm{NH}}_4\mathrm{Cl}\to {\mathrm{CaCl}}_2+2{\mathrm{NH}}_3+2{\mathrm{H}}_2\mathrm{O}$

If $5.35\mathrm{g}$ of ammonium chloride is used, calculate:

(a) The mass of calcium chloride formed

(b) The volume, at STP of ${\mathrm{NH}}_3$ liberated.

Q. The number of Faradays $\left(F\right)$ required to produce $9\text{g}$ of aluminium from molten $AlC{l}_3$ is
(Atomic mass of $Al=27{\text{g mol}}^{–1})$

1. $2$
2. $3$
3. $1$
4. $4$

Q.

The value of ${\mathrm{K}}_{\mathrm{c}}$ is $64$ at $800K$ for the reaction ${\mathrm{N}}_2\left(\mathrm{g}\right)+3{\mathrm{H}}_2\left(\mathrm{g}\right)\rightleftharpoons 2{\mathrm{NH}}_3$. The value of ${\mathrm{K}}_{\mathrm{c}}$ for the following reaction is :

${\mathrm{NH}}_3\rightleftharpoons \frac{1}{2}{\mathrm{N}}_2\left(\mathrm{g}\right)+\frac{3}{2}{\mathrm{H}}_2\left(\mathrm{g}\right)$

1. $\frac{1}{4}$

2. $8$

3. $\frac{1}{8}$

4. $\frac{1}{64}$

Q. Consider the following cell reaction:
$2Fe\left(s\right)+O_2\left(g\right)+4H^{+}\left(aq\right)\to 2F{e}^{2+}\left(aq\right)+2H_{2}O\left(l\right);E^{\circ }=1.67V$
At $\left[F{e}^{2+}\right]={10}^{-3}M,P_{\left(O_2\right)}=0.1atm$ and pH = 3, the cell potential at $25{}^{\circ }C$ is
(given: $\frac{2.303RT}{F}=0.0591$)

Q. 2. Two half-reactions of an electrochemical cell are given below : MnO – 4 (aq) + 8H + (aq) + 5e – → Mn 2+ (aq) + 4H 2 O (I) , E° = 1.51 V Sn 2+ (aq) → Sn 4+ (aq) + 2e – , E° = + 0.15 V. Construct the redox reaction equation from the two half-reactions and calculate the cell potential from the standard potentials and predict if the reaction is reactant or product favoured.

Q. The hydrogen electrode is dipped in a solution of $pH=3$ at ${25}^{\circ }C$. The potential of the cell would be (the value of $2.303\frac{RT}{F}$is $0.059V$

1. – 0.177 V
2. 0.087 V
3. 0.177 V
4. 0.059 V

Q.

E° for F2 + 2e- -> 2F- is 2.8V, E° for 1÷2 F2 + e -> F- is

Ans : 2.8V

Please give detailed explanation as I won't be able to understand concise answers .

Q. For the following electrochemical cell at 298 K,
$Pt\left(s\right)|H_2(g,1bar)|H^{+}(aq,1M)||M^{4+}\left(aq\right),M^{2+}\left(aq\right)|Pt\left(s\right)$
$E_{cell}=0.092Vwhen\frac{[M^{2+}+(aq\left)\right]}{\left[M^{4+}\right(aq\left)\right]}={10}^x$
$Given:E_{M^{4+}/M^{2+}}^{\circ }=0.151V;2.303\frac{RT}{F}=0.059V$
The value of x is

1. -2
2. -1
3. 1
4. 2

Q.

The standard reduction electrode potential of four elements A, B, C and D are $0.8\mathrm{V},0.2\mathrm{V},–1.8\mathrm{V}$ and $–0.5\mathrm{V}$ respectively, the element with the highest reducing power is

1. A

2. B

3. C

4. D

Q.

The emf of the cell $Ag|AgI|KI\left(0.05M\right)||AgN{O}_3\left(0.05M\right)Ag$ is $0.788V$. Calculate the solubility product of $AgI$.

1. 1.10 x 10^-16

2. 25 X 10^-13

3. 6.6 x 10^-19
4. 8 x 10^-11

Q. The number of Faradays $\left(F\right)$ required to produce $2.3\text{g}$ of sodium from molten $NaCl$ (Atomic mass of $Na=23{\text{g mol}}^{-1}$) is:

1. $0.2$
2. $0.1$
3. $0.4$
4. $0.5$

Q. A device which converts chemical energy into electrical energy produced in redox reactions is called

1. Electrolytic
2. Electric
3. Chemical
4. Electrochemical

Q. The solution of $CuS{O}_4$ in which $Cu$ rod is dipped is diluted to 10 times the reduction electrode potential will be

1. Reduces by 0.03 V
2. Increases by 1 V
3. Reduces by 1 V
4. Increases by 0.03 V

Q.

The concentration of potassium ions inside a biological cell is at least twenty times higher than the outside. The resulting potential difference across the cell is important in several processes such as transmission of nerve impulses and maintaining the ion balance. A simple model for such a concentration cell involving a metal M is:
$M\left(s\right)|M^{+}$ (aq;0.05 molar)||$M^{+}$ (aq;1 molar)|M(s)
For the above electrolytic cell the magnitude of the cell potential $|E_{cell}|=70mV$.

For the above cell

1. $E_{cell}<0;\Delta G>0$

2. $E_{cell}>0;\Delta G<0$

3. $E_{cell}>0;\Delta G^0>0$

4. $E_{cell}>0;\Delta G^0<0$

Q. In the reaction :
$A+2B\iff C+2D$ the Initial rate $\frac{-d\left[A\right]}{dt}$
at t = 0 was found to be $2.6\times {10}^{-2}Mse{c}^{-1}.$ What is the value of $\frac{-d\left[B\right]}{dt}$ at t = 0 in Msec${}^{-1}$?

1. $2.6\times {10}^{-2}$
2. $0.1$
3. $5.2\times {10}^{-2}$
4. $6.5\times {10}^{-3}$

Q. do all the metals posses a closed packed structure name the different structure exhibited and gives their packing fraction

Q.

Statements about heavy water are given below:

$\left(A\right)$Heavy water is used in exchange reactions for the study of reaction mechanisms.

$\left(B\right)$ Heavy water is prepared by exhaustive electrolysis of water.

$\left(C\right)$ Heavy water has a higher boiling point than ordinary water.

$\left(D\right)$ The viscosity of $H_{2}O$ is greater than $D_{2}O$.

Which of the above statements are correct?

1. A and B only

2. A and D only

3. A, B and C only

4. A and C only

Q. Taj Mahal is being slowly disfigured and discoloured. This is primarily due to :-

1. Acid rain
2. Soil pollution
3. Water pollution
4. Global warming

Q. In a galvanic cell, anode is :

1. negatively charged
2. positively charged
3. neutral
4. both negatively and positively charged.

Q.

1 mole of equimolar mixture of ferric oxalate and ferrous oxalate will require x mole of $KMn{O}_4$ in acidic medium for complete oxidation, x is

1. 0.9 mole

2. 0.3 mole

3. 1.8 mole

4. 0.6 mole

Q.

Write Nernst equation for daniel cell at equilibrium condition and derive relationship between${{\mathrm{E}}^{°}}_{\mathrm{cell}}$ and equilibrium constant $\left({\mathrm{K}}_{\mathrm{c}}\right)$.

Q.

The single electrode potential of chloride electrode of [Cl^‑] = 0.1 M is (E^oCl₂/Cl^‑ is 1.36 V)

1. 0.272 V

2. 1.36 V

3. 0.136 V

4. 1.419 V

Q. 49. What is Nerst Distribution law. Explain in detail giving names of all constants.

Q. The value of the reaction quotient 'Q' for the following cell is Y.
$Cr\left(s\right)|C{r}^{3+}\left(aq\right)\left(0.1M\right)||C{u}^{2+}\left(aq\right)\left(0.5M\right)|Cu\left(s\right)$
Find the value of Y

Q. Given:
Pt (s) | $C{l}^{-}$($C_1$) | $C{l}_2$(g)($P_1$ atm) || $C{l}_2$(g)($P_1$ atm)| $C{l}^{-}$($C_2$)| Pt (s)
Identify in which of the following condition working of cell takes place:

1. $C_1$ > $C_2$ and $P_1$ = $P_2$
2. $P_2$ > $P_1$ and $C_1$ = $C_2$
3. $C_1$ < $C_2$ and $P_1$ = $P_2$
4. $P_2$ < $P_1$ and $C_1$ = $C_2$

Q. The standard reduction potentials of $Ag,Cu,Co$ and $Zn$ is $0.799,$ $0.337,$ $-0.277,$ $-0.762$V respectively. Which of the following cells will have maximum cell e.m.f.?

1. $Zn|Z{n}^{2+}\left(1M\right)||C{u}^{2+}\left(1M\right)|Cu$
2. $Cu|C{u}^{2+}\left(1M\right)||A{g}^{+}\left(1M\right)|Ag$
3. $Zn|Z{n}^{2+}\left(1M\right)||A{g}^{+}\left(1M\right)|Ag$
4. $Zn|Z{n}^{2+}\left(1M\right)||C{o}^{2+}\left(1M\right)|Co$

Q. Define electrochemical cell. What happens if external potential applied becomes greater than $E_{cell}$ of electrochemical cell?

Q. In a $H_2-O_2$ fuel cell, 8.96 L of hydrogen at STP reacts in 15 minutes.​ The average current produced in amperes is:​

1. $8.577amp$
2. $85.77amp$
3. $857.7amp$
4. $8577amp$