Which of the following reactions is $NOT$ an example of a redox reaction?

Which of the following combinations does not evolve $Cl_2$ gas?

$H_2O_2$ reduces $KMnO_4$ in acidic medium to '$x$' and in basic medium to '$y$'. What are $x$ and $y$?

Consider the following list of reagents:
Acidified $K_2Cr_2O_7$,alkaline $KMnO_4$,$CuSO_4$,$H_2O_2$,$Cl_2$,$O_3$,$FeCl_3$,$HNO_3$ and $Na_2S_2O_3$. The total number of reagents that can oxidise aqueous iodide to iodine is

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$Na_2S_2O_3 + BaCl_2 \longrightarrow BaS_2O_3 \downarrow + 2NaCl$

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