Electrochemical Series

Q.

During the electrolysis of acidified water using platinum electrodes, hydrogen is liberated at the ______ and oxygen at the _______.

Q.

The ions which are discharged during electrolysis of aqueous ${\mathrm{CuSO}}_4$, using copper electrodes are _?

Q. In the electrolysis of very dilute NaOH using platinum electrodes:-

1. $H_2$ is evolved at cathode and $O_2$ at anode
2. $N{a}_2{O}_2$ is produced
   
3. $H_2{O}_2$ is produced
   
4. $O_2$ is produced at cathode and $H_2$ at anode

Q.

Copper does not react with Hydrochloric acid or dilute Sulphuric acid. Explain it.

Q. For the feasibility of a redox reaction in a cell, the emf of the cell should be:

1. Zero
2. Positive
3. Negative
4. Fixed

Q.

Which of the following cannot work as oxidising agent

1. O2

2. KMnO4

3. I2

4. None of these

Q. $\text{Statement I:}$ When copper rod is placed in aqueous solution of $AgN{O}_3$, the solution turns blue in colour.
$\text{Statement II:}$ Intensity of blue colour increases when zinc rod is placed in aqueous solution of $CuS{O}_4$.
In the light of above statements, choose the correct option below

1. Statement I incorrect and statement II is correct
2. Both the statements I and statement II are correct
3. Both the statements I and statement II are incorrect
4. Statement I is correct and Statement II is incorrect

Q.

The standard reduction potential data at ${25}^{\circ }C$ is given below.

$E^{\circ }\left(F{e}^{3+}/F{e}^{2+}\right)=0.77V;E^{\circ }\left(F{e}^{2+}/Fe\right)=-0.44V;E^{\circ }\left(C{u}^{2+}/Cu\right)=0.34V;E^{\circ }\left(C{u}^{+}/Cu\right)=+0.52V;E^{\circ }\left(O_2\right(g)+4H^{+}+4e^{-})\to 2H_{2}O=+1.23V;E^{\circ }\left(O_2\right(g)+2H_{2}O+4e^{-})\to 4O{H}^{-}=+0.40V{E}^{\circ }\left(C{r}^{3+}/Cr\right)=-0.74V;E^{\circ }\left(C{r}^{2+}/Cr\right)=+0.91V$

Match $E^{\circ }$ of the rebox pair in Column I with the values given in Column II and select the correct answer using the code given below the lists.

$\begin{array}{cc}ColumnI& ColumnII\\ P.E^{\circ }\left(F{e}^{3+}/Fe\right)& 1.-0.18V\\ Q.E^{\circ }(4H_{2}O\rightleftharpoons 4H^{+}+4O{H}^{-})& 2.-0.4V\\ R.E^{\circ }(C{u}^{2+}+Cu\to 2C{u}^{+})& 3.-0.04V\\ S.E^{\circ }\left(C{r}^{3+}/C{r}^{2+}\right)& 4.-0.83V\end{array}$

1. P - (4) Q - (1) R - (2) S - (3)

2. P - (2) Q - (3) R - (4) S - (1)

3. P - (1) Q - (2) R - (3) S - (4)

4. P - (3) Q - (4) R - (1) S - (2)

Q. Which of the following statements are correct?

(i) The electrolysis of aqueous NaCl produces hydrogen gas at the cathode and chlorine gas at the anode

(ii) The electrolysis of a $CuS{O}_4$ solution using Pt electrodes causes the liberation of $O_2$ at the anode and the deposition of copper at the cathode

(iii) Oxygen and hydrogen are produced at the anode and cathode during the electrolysis of dilute aqueous solution of $H_{2}S{O}_4$

(iv) All electrolytic reactions are redox reactions

1. Only (i) is correct
2. (i), (ii) are correct
3. (i), (iv) are correct
4. All are correct

Q. The standard reduction potentials at 298 K for the following half reactions are given:

Which is the strongest reducing agent?
$Z{n}^{2+}(aq.)+2e\rightleftharpoons Zn\left(s\right);-0.762$
$C{r}^{3+}\left(aq\right)+3e\rightleftharpoons Cr\left(s\right);-0.740$
$2H^{+}\left(aq\right)+2e\rightleftharpoons H_2\left(g\right);0.00$
$F{e}^{3+}\left(aq\right)+e\rightleftharpoons F{e}^{2+}\left(aq\right);0.770$

1. $Zn\left(s\right)$
2. $Cr\left(s\right)$
3. $H_2\left(g\right)$
4. $F{e}^{2+}\left(aq\right)$

Q. for metals amd non.metals.high reduction potential reduces one with lowerRP or Lower will replace one with higher RP??

Q. $2Na\left(s\right)+2H_{2}O\to 2N{a}^{+}\left(aq\right)+2O{H}^{-}\left(aq\right)+H_2\left(g\right)$
Match the oxidation number of the following atoms in various species.

Q. Find the ratio of molar accounts of H2SO4 needed to preciptise metal ions from 20ml each of 1M cd(NO3)2 and 0.5 M cuso4??

Q. 9 MnO ions are reduced in acidic condition toMn2 ions whereas they are reduced in neutracondition to MnO2 The oxidation of 25 mL of asolution X containing Fe ions required in acidiccondition 20 mL of a solution Y containing Mn0ions. What volume of solution Y would be requiredto oxidise 25 mL of solution X containing Fe+ ionsin neutral condition?(a) 11.4 mL(cY 33.3 mL(b) 12.0 mL(d) 35.0 mL

Q. Find the emf of the following cell. (Take $\frac{RTln10}{F}=0.06$
$\begin{array}{c}Pt,H_2\left(g\right)/H^{+}\left(aq\right)//H^{+}\left(aq\right)/H_2\left(g\right),Pt\\ 10atm{10}^{-9}M{10}^{-3}M0.1atm\end{array}$

1. 0.24 V
2. 0.48 V
3. 0.42 V
4. 0.84 V

Q.

A solution containing 1 mol per litre of each $Cu(N{O}_3{)}_2,AgN{O}_3,$ and $H{g}_2(N{O}_3{)}_2$ is being electrolyzed by using inert electrodes. The values of standard electrode potentials in volts (reduction potential) are
$Ag|A{g}^{⨁}=+0.80,2Hg|H{g}_2^{2+}=+0.79$
$Cu|C{u}^{2+}=+0.34,Mg|M{g}^{2+}=-2.37$
with increasing voltage, the sequence of deposition of metals at the cathode will be
(IIT-JEE, 1984)

1. $Ag,Hg,Cu,Mg$

2. $Mg,Cu,Hg,Ag$

3. $Ag,Hg,Cu$

4. $Cu,Hg,Ag$

Q.

For the reduction of $N{O}_3^{\ominus }$ ion in an aqueous solution, $E^{\ominus }$ is +0.96 V, the values of $E^{\ominus }$ for some metal ions are given below:
$\left(i\right)V^{2+}\left(aq\right)+2e^{-}\to V;E^{\ominus }=-1.19V$
$\left(ii\right)F{e}^{3+}\left(aq\right)+3e^{-}\to Fe;E^{\ominus }=-0.04V$
$\left(iii\right)A{u}^{3+}\left(aq\right)+3e^{-}\to Au;E^{\ominus }=+1.40V$
$\left(iv\right)H{g}^{2+}\left(aq\right)+2e^{-}\to Hg;E^{\ominus }=+0.86V$

The pair(s) of metals that is/are oxidized by $N{O}_3^{\ominus }$ in aqueous solution is/are
(IIT-JEE, 2010)

1. $Fe$ and $Au$

2. $Hg$ and $Fe$

3. $V$ and $Hg$

4. $Fe$ and $V$

Q. Consider the following standard oxidation potentials $\left(\text{at}{25}^{\circ }\text{C}\right)$
$E_{Ag|A{g}^{+}}^{\circ }:-0.799\text{V};E_{Hg|H{g}^{2+}}^{\circ }:-0.789\text{V};E_{Mg|M{g}^{2+}}^{\circ }:+2.37\text{V};$
$E_{Mn|M{n}^{2+}}^{\circ }:+1.18\text{V};E_{Sn|S{n}^{2+}}^{\circ }:0.136\text{V}$.
Which of the following statement(s) is/are incorrect under standard conditions?

1. $Sn$ can displace $Mg$ and $Ag$ from their solutions
2. $Ag$ can displace $Hg$ and $Mg$ from their solutions
3. $Mn$ can displace $Sn,Hg$ and $Ag$ from their solutions
4. $Mn$ can displace $Sn,Mg$ and $Hg$ from their solutions

Q.

For the reduction of $N{O}_3^{\ominus }$ ion in an aqueous solution, $E^{\ominus }$ is +0.96 V, the values of $E^{\ominus }$ for some metal ions are given below:
$\left(i\right)V^{2+}\left(aq\right)+2e^{-}\to V;E^{\ominus }=-1.19V$
$\left(ii\right)F{e}^{3+}\left(aq\right)+3e^{-}\to Fe;E^{\ominus }=-0.04V$
$\left(iii\right)A{u}^{3+}\left(aq\right)+3e^{-}\to Au;E^{\ominus }=+1.40V$
$\left(iv\right)H{g}^{2+}\left(aq\right)+2e^{-}\to Hg;E^{\ominus }=+0.86V$

The pair(s) of metals that is/are oxidized by $N{O}_3^{\ominus }$ in aqueous solution is/are
(IIT-JEE, 2010)

1. $Fe$ and $Au$

2. $Hg$ and $Fe$

3. $V$ and $Hg$

4. $Fe$ and $V$

Q. The standard reduction potentials at 298 K for the following half reactions are given:

Which is the strongest reducing agent?
$Z{n}^{2+}(aq.)+2e\rightleftharpoons Zn\left(s\right);-0.762$
$C{r}^{3+}\left(aq\right)+3e\rightleftharpoons Cr\left(s\right);-0.740$
$2H^{+}\left(aq\right)+2e\rightleftharpoons H_2\left(g\right);0.00$
$F{e}^{3+}\left(aq\right)+e\rightleftharpoons F{e}^{2+}\left(aq\right);0.770$

1. $Zn\left(s\right)$
2. $Cr\left(s\right)$
3. $H_2\left(g\right)$
4. $F{e}^{2+}\left(aq\right)$

Q. Explain redox reaction on the basis of electron transfer. Give suitable examples.

Q. Arrange $Zn$, $Pb$ and $Al$ in the decreasing order of their reducing powers under standard conditions.
Given: $E_{Z{n}^{2+}|Zn}^0=-0.76V,E_{P{b}^{2+}|Pb}^0=-0.13V$
$E_{A{l}^{3+}|Al}^0=-1.66V$

1. $Zn>Al>Pb$
2. $A1>Pb>Zn$
3. $Zn>Al>Pb$
   
4. $Al>Zn>Pb$

Q. Given, $E_{C{r}^{(}3+)/Cr}^0=-0.74V;E_{Mn{O}_4^{-}/M{n}^{2+}}^0=1.51V$
$E_{C{r}_2{O}_7^{2-}/C{r}^{3+}}^0=1.33V;E_{Cl/C{l}^{-}}^0=1.36V$
Based on the data given above strongest oxidising agent will be

1. $C{l}^{-}$
2. $C{r}^{3+}$
3. $M{n}^{2+}$
4. $Mn{O}_4^{-}$

Q. Which of the following statement is true?
$A{g}^{+}\left(aq\right)+e^{-}\to Ag\left(s\right);E^0=0.80V$
$C{u}^{2+}\left(aq\right)+2e^{-}\to Cu\left(s\right);E^0=0.34V$

1. $Cu$ displace $Ag$ from $AgN{O}_3$
2. $AgN{O}_3$ solution cannot be stored in $Cu$ vessel
3. Both (a) and (c)
4. $CuS{O}_4$ solution cannot be stored in $Ag$ vessel

Q. Which of the following of metals, when coupled, will give maximum EMF for a voltaic cell?
Given:
$A{u}^{+}\left(aq\right)+e^{-}\to Au\left(s\right);E^0=1.69V$
$C{u}^{2+}\left(aq\right)+2e^{-}\to Cu\left(s\right);E^0=0.34V$
$P{b}^{2+}\left(aq\right)+2e^{-}\to Pb\left(s\right);E^0=-0.13V$
$F{e}^{2+}\left(aq\right)+2e^{-}\to Fe\left(s\right);E^0=-0.44V$
$C{a}^{2+}\left(aq\right)+2e^{-}\to Ca\left(s\right);E^0=-2.87V$

1. $Pb\text{and}Au$
2. $Ca\text{and}Cu$
3. $Cu\text{and}Au$
4. $Fe\text{and}Au$

Q. among alkali metal negative electrode potential of lithium is highest or lowest?

Q. In view of their low ionization energies, the alkali metals are :

1. strong reducing agents
2. strong oxidizing agents
3. weak oxidizing agents
4. weak reducing agents

Q. why Li is less reactive towards water

Q. Find the emf of the following cell. (Take $\frac{RTln10}{F}=0.06$
$\begin{array}{c}Pt,H_2\left(g\right)/H^{+}\left(aq\right)//H^{+}\left(aq\right)/H_2\left(g\right),Pt\\ 10atm{10}^{-9}M{10}^{-3}M0.1atm\end{array}$

Q. Electrochemical series gives the order of reduction potentials of elements and ions in an increasing/decreasing trend.

1. True
2. False