The element that does not show a disproportionation tendency is/are:

1. Cl

2. Br

3. F

4. I

Assertion: In the presentation ${\mathrm{E}}_{{\mathrm{Fe}}^{3+}/{\mathrm{Fe}}^{2+}}^{⊝}$ and ${\mathrm{E}}_{{\mathrm{Cu}}^{2+}/\mathrm{Cu}}^{⊝}$, ${\mathrm{Fe}}^{3+}/{\mathrm{Fe}}^{2+}$ and ${\mathrm{Cu}}^{2+}/\mathrm{Cu}$ are redox couples.

Reason: A redox couple is the combination of the oxidised and reduced forms of a substance involved in an oxidation or reduction half cell.

Given below are two statements: 

Which of the following is not an example of redox reaction?

1. $\mathrm{CuO}+{\mathrm{H}}_2\to \mathrm{Cu}+{\mathrm{H}}_2\mathrm{O}$

2. ${\mathrm{Fe}}_2{\mathrm{O}}_3+3\mathrm{CO}\to 2\mathrm{Fe}+3{\mathrm{CO}}_2$

3. $2\mathrm{K}+{\mathrm{F}}_2\to 2\mathrm{KF}$

4. ${\mathrm{BaCl}}_2+{\mathrm{H}}_2{\mathrm{SO}}_4\to {\mathrm{BaSO}}_4+2\mathrm{HCl}$

The more positive the value of ${\mathrm{E}}^{⊝}$, the greater is the tendency of the species to get reduced. Using the standard electrode potential of redox couples given below find out which of the following is the strongest oxidising agent.

${\mathrm{E}}^{⊝} \mathrm{values}: {\mathrm{Fe}}^{3+}/{\mathrm{Fe}}^{2+}=+0.77$
${\mathrm{I}}_2\left(\mathrm{s}\right)/{\mathrm{I}}^{-}=+0.54;$
${\mathrm{Cu}}^{2+}/\mathrm{Cu}=+0.34;$
${\mathrm{Ag}}^{+}/\mathrm{Ag}=0.80 \mathrm{V}$

1. Fe³⁺

2. I₂(s)

3. Cu²⁺

4. Ag⁺

${\mathrm{E}}^{\Theta }$ values of some redox couples are given below. On the basis of these values choose the correct option.

${\mathrm{E}}^{\mathrm{\Theta }} \mathrm{values}: {\mathrm{Br}}_2/{\mathrm{Br}}^{-}=+1.90$
${\mathrm{Ag}}^{+}/\mathrm{Ag}\left(\mathrm{s}\right)=+0.80$
${\mathrm{Cu}}^{2+}/\mathrm{Cu}\left(\mathrm{s}\right)=+0.34;$
${\mathrm{I}}_2\left(\mathrm{s}\right)/{\mathrm{I}}^{-}=+0.54$

Using the standard electrode potential, find out the pair between which redox reaction is not feasible.

${\mathrm{E}}^{⊝} \mathrm{values}: {\mathrm{Fe}}^{3+}/{\mathrm{Fe}}^{2+}=+0.77; {\mathrm{I}}_2/{\mathrm{I}}^{-}=+0.54;$
${\mathrm{Cu}}^{2+}/\mathrm{Cu}=+0.34; {\mathrm{Ag}}^{+}/\mathrm{Ag}=+0.80 \mathrm{V}$

1. Fe³⁺ and I^-

2. Ag⁺ and Cu

3. Fe³⁺ and Cu

4. Ag and Fe³⁺

In the reactions given below, thiosulphate reacts differently with iodine than with bromine.

$2{\mathrm{S}}_2{\mathrm{O}}_3^{2-}+{\mathrm{I}}_2\to {\mathrm{S}}_4{\mathrm{O}}_6^{2-}+2{\mathrm{I}}^{-}$

${\mathrm{S}}_2{\mathrm{O}}_3^{2-}+2{\mathrm{Br}}_2+5{\mathrm{H}}_2\mathrm{O}\to 2{\mathrm{SO}}_4^{2-}+2{\mathrm{Br}}^{-}+10{\mathrm{H}}^{+}$

Choose the statements among the following that best describe the above dual behaviour of thiosulphate.

The incorrect statement regarding the rule to find the oxidation number among the following is-

In which of the following compounds, an element exhibits two different oxidation state?

1. ${\mathrm{NH}}_2\mathrm{OH}$

2. ${\mathrm{NH}}_4{\mathrm{NO}}_3$

3. ${\mathrm{N}}_2{\mathrm{H}}_4$

4. ${\mathrm{N}}_3\mathrm{H}$