Electrochemical Series

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

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.

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(s)
2. Fe²⁺(aq)
3. H₂(g)
4. Cr(s)

Q. Given
$E_{C{l}_2/C{l}^{-}}^{\circ }=1.36V,E_{C{r}^{3+}/Cr}^{\circ }=-0.74V{E}_{C{r}_2{O}_7^{2-}/C{r}^{3+}}^{\circ }=1.33V,E_{Mn{O}_4^{-}/M{n}^{2+}}^{\circ }=1.51V$
Among the following, the strongest reducing agent is

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

Q. Electrolysis of an aqueous solution of which salt produces hydrogen at cathode, chlorine at anode and sodium hydroxide in the solution?

1. Sodium chloride
2. Sodium oxide
3. Sodium hydroxide
4. Sodium hydride

Q. Give equations to show how you can prepare zinc chloride starting from the following reactants.
(a) zinc
(b) zinc oxide
(c) zinc carbonate

Q. The standard reduction potentials at 298 K for the following half-reactions are given against each.
$Z{n}^{2+}\left(aq\right)+2e=Zn\left(s\right);-0.762V$
$C{r}^{3+}\left(aq\right)+3e=Cr\left(s\right);-0.74V$
$2H^{+}+2e=H_2\left(g\right);\pm -0.0V$
$F{e}^{3+}\left(aq\right)+e=F{e}^{2+}\left(aq\right);+0.77V$

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