When an acidic solution of $K_2Cr_2O_7$ is added to $Na_2SO_3$,it turns green. Which of the following compounds is formed in this reaction?

Consider the following reactions (unbalanced):
$Zn +$ hot conc. $H_2SO_4 \rightarrow G + R + X$
$Zn +$ conc. $NaOH \rightarrow T + Q$
$G + H_2S + NH_4OH \rightarrow Z$ (a precipitate) $+ X + Y$
Choose the correct option$(s)$.
$(1)$ The oxidation state of $Zn$ in $T$ is $+1$
$(2)$ Bond order of $Q$ is $1$ in its ground state
$(3)$ $Z$ is dirty white in colour
$(4)$ $R$ is a $V$-shaped molecule

How many moles of $MnO_4^-$ are required to completely oxidize $1 \ mol$ of ferrous oxalate in an acidic medium?

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$Pb_3O_4 + 4HNO_3 \rightarrow 2Pb(NO_3)_2 + PbO_2 + 2H_2O$

$O_3 + 2KI_{(aq)} \rightarrow ?$ The product of the reaction is:

Acidified potassium permanganate solution is decolourised by