Potassium permanganate acts as an oxidant in neutral,alkaline,as well as acidic media. The final products obtained from it in the three conditions are,respectively:

The redox reaction among the following is

Match List-$I$ with the List-$II$.

List-$I$ (Reaction)	List-$II$ (Type of redox reaction)
$A$. $N_{2(g)} + O_{2(g)} \rightarrow 2 NO_{(g)}$	$I$. Decomposition
$B$. $2 Pb(NO_3)_{2(s)} \rightarrow 2 PbO_{(s)} + 4 NO_{2(g)} + O_{2(g)}$	$II$. Displacement
$C$. $2 Na_{(s)} + 2 H_2 O_{(l)} \rightarrow 2 NaOH_{(aq)} + H_{2(g)}$	$III$. Disproportionation
$D$. $2 NO_{2(g)} + 2 OH^-_{(aq)} \rightarrow NO^-_{2(aq)} + NO^-_{3(aq)} + H_2 O_{(l)}$	$IV$. Combination

Choose the correct answer from the options given below:

$1 \text{ mole of } H_2C_2O_4 \text{ is oxidised by } x \text{ mole of } MnO_4^- \text{ in strong basic medium and } 1 \text{ mole of } NaHC_2O_4 \text{ is oxidised by } y \text{ mole of } MnO_4^- \text{ in acidic medium. Ratio of } x/y \text{ is}$

Observe the following reactions:
$(i)$ $2 KClO_{3(s)} \xrightarrow{\Delta} 2 KCl_{(s)} + 3 O_{2(g)}$
$(ii)$ $2 H_2O_{2(aq)} \xrightarrow{\Delta} 2 H_2O_{(l)} + O_{2(g)}$
$(iii)$ $AgNO_{3(aq)} + KCl_{(aq)} \longrightarrow AgCl_{(s)} + KNO_{3(aq)}$
$(iv)$ $2 Na_{(s)} + \frac{1}{2} O_{2(g)} \longrightarrow Na_2O_{(s)}$
The number of redox reactions in this list is

In which of the following conversions does a blue colour appear?