NCERT Solutions for Chapter: Redox Reactions, Exercise 1: Long Answer Type

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

On the basis of standard electrode potential values, suggest which of the following reactions would take place?

${\mathrm{E}}^{⊝}$ values are given as:

$$\begin{gathered} {{\mathrm{E}}^{\circ }}_{{\mathrm{Cu}}^{2+}/\mathrm{Cu}}=0.34\mathrm{V}, {{\mathrm{E}}^{\circ }}_{{\mathrm{Zn}}^{2+}/\mathrm{Zn}}=-0.76\mathrm{V} \\ {{\mathrm{E}}^{\circ }}_{{\mathrm{Mg}}^{2+}/\mathrm{Mg}}=-2.36\mathrm{V}, {{\mathrm{E}}^{\circ }}_{{\mathrm{Fe}}^{2+}/\mathrm{Fe}}=-0.44\mathrm{V} \\ {{\mathrm{E}}^{\circ }}_{{\mathrm{Br}}_2/\mathrm{Br}}=+1.09\mathrm{V}, {{\mathrm{E}}^{\circ }}_{{\mathrm{Cl}}_2/{\mathrm{Cl}}^{-}}=+1.36\mathrm{V} \\ {{\mathrm{E}}^{\circ }}_{{\mathrm{Cd}}^{2+}/\mathrm{Cd}}=-0.40\mathrm{V} \end{gathered}$$

$$\begin{gathered} \left(\mathrm{i}\right) \mathrm{Cu} + {\mathrm{Zn}}^{2+} \to {\mathrm{Cu}}^{2+} + \mathrm{Zn} \\ \left(\mathrm{ii}\right) \mathrm{Mg} + {\mathrm{Fe}}^{2+} \to {\mathrm{Mg}}^{2+} + \mathrm{Fe} \\ \left(\mathrm{iii}\right) {\mathrm{Br}}_2 + 2{\mathrm{Cl}}^{–} \to {\mathrm{Cl}}_2 + 2{\mathrm{Br}}^{–} \\ \left(\mathrm{iv}\right) \mathrm{Fe} + {\mathrm{Cd}}^{2+} \to \mathrm{Cd} + {\mathrm{Fe}}^{2+} \end{gathered}$$

Why does fluorine not show disproportionation reaction?

Write redox couples involved in the reactions (i) to (iv).

$$\begin{gathered} \left(\mathrm{i}\right) \mathrm{Cu} + {\mathrm{Zn}}^{2+} \to {\mathrm{Cu}}^{2+} + \mathrm{Zn} \\ \left(\mathrm{ii}\right) \mathrm{Mg} + {\mathrm{Fe}}^{2+} \to {\mathrm{Mg}}^{2+} + \mathrm{Fe} \\ \left(\mathrm{iii}\right) {\mathrm{Br}}_2 + 2{\mathrm{Cl}}^{–} \to {\mathrm{Cl}}_2 + 2{\mathrm{Br}}^{–} \\ \left(\mathrm{iv}\right) \mathrm{Fe} + {\mathrm{Cd}}^{2+} \to \mathrm{Cd} + {\mathrm{Fe}}^{2+} \end{gathered}$$

Find out the oxidation number of chlorine in the following compounds and arrange them in increasing order of oxidation number of chlorine.

${\mathrm{NaClO}}_4, {\mathrm{NaClO}}_3, \mathrm{NaClO}, {\mathrm{KClO}}_2, {\mathrm{Cl}}_2{\mathrm{O}}_7, {\mathrm{ClO}}_3, {\mathrm{Cl}}_2\mathrm{O}, \mathrm{NaCl}, {\mathrm{Cl}}_2, {\mathrm{ClO}}_2$

Which oxidation state is not present in any of the above compounds?

Which method can be used to find out strength of reductant/oxidant in a solution? Explain with an example.